For the unfolding of an organism or the theory that plants and animals develop in this way see epigenesis (biology). For epigenetics in robotics see developmental robotics.
This article is part of the series on:
Gene expression a Molecular biology topic (portal) (Glossary) Introduction to Genetics General flow: DNA > RNA > Protein special transfers (RNA > RNA RNA > DNA Protein > Protein) Genetic code Transcription Transcription (Transcription factors RNA Polymerasepromoter)
Prokaryotic / Archaeal / Eukaryotic post-transcriptional modification (hnRNASplicing) Translation Translation (RibosometRNA)
Prokaryotic / Archaeal / Eukaryotic post-translational modification (functional groups peptides structural changes) gene regulation epigenetic regulation (Genomic imprinting) transcriptional regulation post-transcriptional regulation (sequestration alternative splicingmiRNA) translational regulation post-translational regulation (reversibleirreversible) This box: view talk
In biology and specifically genetics epigenetics is the study of inherited changes in phenotype (appearance) or gene expression caused by mechanisms other than changes in the underlying DNA sequence hence the name epi- (Greek: - over above) -genetics. These changes may remain through cell divisions for the remainder of the cell's life and may also last for multiple generations. However there is no change in the underlying DNA sequence of the organism;1 instead non-genetic factors cause the organism's genes to behave (or "express themselves") differently.2
The best example of epigenetic changes in eukaryotic biology is the process of cellular differentiation. During morphogenesis totipotent stem cells become the various pluripotent cell lines of the embryo which in turn become fully differentiated cells. In other words a single fertilized egg cell the zygote changes into the many cell types including neurons muscle cells epithelium blood vessels etc. as it continues to divide. It does so by activating some genes while inhibiting others.3 Contents 1 Etymology and definitions 2 Molecular basis of epigenetics 3 Mechanisms 3.1 DNA methylation and chromatin remodeling 3.2 RNA transcripts and their encoded proteins 3.3 Prions 3.4 Structural inheritance systems 4 Functions and consequences 4.1 Development 4.2 Medicine 4.3 Evolution 4.4 Transgenerational epigenetic observations 5 Epigenetic effects in humans 5.1 Genomic imprinting and related disorders 5.2 Transgenerational epigenetic observations 5.3 Cancer and developmental abnormalities 5.4 Twin studies 6 Epigenetics in microorganisms 7 See also 8 Further reading 9 Notes and references 10 External links // Etymology and definitions epigenetic mechanisms
Epigenetics (as in "epigenetic landscape") was coined by C. H. Waddington in 1942 as a portmanteau of the words genetics and epigenesis.4 Epigenesis is an old5 word which has more recently been used (see preformationism for historical background) to describe the differentiation of cells from their initial totipotent state in embryonic development. When Waddington coined the term the physical nature of genes and their role in heredity was not known; he used it as a conceptual model of how genes might interact with their surroundings to produce a phenotype.
Robin Holliday defined epigenetics as "the study of the mechanisms of temporal and spatial control of gene activity during the development of complex organisms."6 Thus epigenetic can be used to describe anything other than DNA sequence that influences the development of an organism.
The modern usage of the word in scientific discourse is more narrow referring to heritable traits (over rounds of cell division and sometimes transgenerationally) that do not involve changes to the underlying DNA sequence.7 The Greek prefix epi- in epigenetics implies features that are "on top of" or "in addition to" genetics; thus epigenetic traits exist on top of or in addition to the traditional molecular basis for inheritance.
The similarity of the word to "genetics" has generated many parallel usages. The "epigenome" is a parallel to the word "genome" and refers to the overall epigenetic state of a cell. The phrase "genetic code" has also been adaptedthe "epigenetic code" has been used to describe the set of epigenetic features that create different phenotypes in different cells
This article is part of the series on:
Gene expression a Molecular biology topic (portal) (Glossary) Introduction to Genetics General flow: DNA > RNA > Protein special transfers (RNA > RNA RNA > DNA Protein > Protein) Genetic code Transcription Transcription (Transcription factors RNA Polymerasepromoter)
Prokaryotic / Archaeal / Eukaryotic post-transcriptional modification (hnRNASplicing) Translation Translation (RibosometRNA)
Prokaryotic / Archaeal / Eukaryotic post-translational modification (functional groups peptides structural changes) gene regulation epigenetic regulation (Genomic imprinting) transcriptional regulation post-transcriptional regulation (sequestration alternative splicingmiRNA) translational regulation post-translational regulation (reversibleirreversible) This box: view talk
In biology and specifically genetics epigenetics is the study of inherited changes in phenotype (appearance) or gene expression caused by mechanisms other than changes in the underlying DNA sequence hence the name epi- (Greek: - over above) -genetics. These changes may remain through cell divisions for the remainder of the cell's life and may also last for multiple generations. However there is no change in the underlying DNA sequence of the organism;1 instead non-genetic factors cause the organism's genes to behave (or "express themselves") differently.2
The best example of epigenetic changes in eukaryotic biology is the process of cellular differentiation. During morphogenesis totipotent stem cells become the various pluripotent cell lines of the embryo which in turn become fully differentiated cells. In other words a single fertilized egg cell the zygote changes into the many cell types including neurons muscle cells epithelium blood vessels etc. as it continues to divide. It does so by activating some genes while inhibiting others.3 Contents 1 Etymology and definitions 2 Molecular basis of epigenetics 3 Mechanisms 3.1 DNA methylation and chromatin remodeling 3.2 RNA transcripts and their encoded proteins 3.3 Prions 3.4 Structural inheritance systems 4 Functions and consequences 4.1 Development 4.2 Medicine 4.3 Evolution 4.4 Transgenerational epigenetic observations 5 Epigenetic effects in humans 5.1 Genomic imprinting and related disorders 5.2 Transgenerational epigenetic observations 5.3 Cancer and developmental abnormalities 5.4 Twin studies 6 Epigenetics in microorganisms 7 See also 8 Further reading 9 Notes and references 10 External links // Etymology and definitions epigenetic mechanisms
Epigenetics (as in "epigenetic landscape") was coined by C. H. Waddington in 1942 as a portmanteau of the words genetics and epigenesis.4 Epigenesis is an old5 word which has more recently been used (see preformationism for historical background) to describe the differentiation of cells from their initial totipotent state in embryonic development. When Waddington coined the term the physical nature of genes and their role in heredity was not known; he used it as a conceptual model of how genes might interact with their surroundings to produce a phenotype.
Robin Holliday defined epigenetics as "the study of the mechanisms of temporal and spatial control of gene activity during the development of complex organisms."6 Thus epigenetic can be used to describe anything other than DNA sequence that influences the development of an organism.
The modern usage of the word in scientific discourse is more narrow referring to heritable traits (over rounds of cell division and sometimes transgenerationally) that do not involve changes to the underlying DNA sequence.7 The Greek prefix epi- in epigenetics implies features that are "on top of" or "in addition to" genetics; thus epigenetic traits exist on top of or in addition to the traditional molecular basis for inheritance.
The similarity of the word to "genetics" has generated many parallel usages. The "epigenome" is a parallel to the word "genome" and refers to the overall epigenetic state of a cell. The phrase "genetic code" has also been adaptedthe "epigenetic code" has been used to describe the set of epigenetic features that create different phenotypes in different cells
Epitwin: Largest Ever Epigenetics Project Launched
One of the most ambitious large-scale projects in Human Genetics has been launched: Epitwin will capture the subtle epigenetic signatures that mark the differences between 5,000 twins on a scale and depth never before attempted, providing key therapeutic targets for the development of drug treatments. The project is a collaboration between TwinsUK, a leading twin research group based at King's ...
One of the most ambitious large-scale projects in Human Genetics has been launched: Epitwin will capture the subtle epigenetic signatures that mark the differences between 5,000 twins on a scale and depth never before attempted, providing key therapeutic targets for the development of drug treatments. The project is a collaboration between TwinsUK, a leading twin research group based at King's ...
methylation on target genes of the EED EZH2 complex Therefore identification of the EED EZH2 target genes involved in cell proliferation will be of great interest Unlike H3 K27 methylation which causes transcriptional silencing H3 K4 methylation has been linked to transcriptional activation Consistent with the
http://www.komabiotech.com/technical/review/epigenetics.htm
Epigenetics: Information from Answers.com
Epigenetic modifications define how genetic information is read and used by cells. ... Epigenetic modifications influence gene expression and enable the ...
Epigenetic modifications define how genetic information is read and used by cells. ... Epigenetic modifications influence gene expression and enable the ...
. Taken to its extreme the "epigenetic code" could represent the total state of the cell with the position of each molecule accounted for in an epigenomic map a diagrammatic representation of the gene expression DNA methylation and histone modification status of a particular genomic region. More typically the term is used in reference to systematic efforts to measure specific relevant forms of epigenetic information such as the histone code or DNA methylation patterns.
Epigenetic was also used by the psychologist Erik Erikson in his Psychosocial development theory. That usage however is of primarily historical interest.8 Molecular basis of epigenetics
The molecular basis of epigenetics is complex. It involves modifications of the activation of certain genes but not the basic structure of DNA. Additionally the chromatin proteins associated with DNA may be activated or silenced. This accounts for why the differentiated cells in a multi-cellular organism express only the genes that are necessary for their own activity. Epigenetic changes are preserved when cells divide. Most epigenetic changes only occur within the course of one individual organism's lifetime but if a mutation in the DNA has been caused in sperm or egg cell that results in fertilization then some epigenetic changes are inherited from one generation to the next.9 This raises the question of whether or not epigenetic changes in an organism can alter the basic structure of its DNA (see Evolution below) a form of Lamarckism.
Specific epigenetic processes include paramutation bookmarking imprinting gene silencing X chromosome inactivation position effect reprogramming transvection maternal effects the progress of carcinogenesis many effects of teratogens regulation of histone modifications and heterochromatin and technical limitations affecting parthenogenesis and cloning.
Epigenetic research uses a wide range of molecular biologic techniques to further our understanding of epigenetic phenomena including chromatin immunoprecipitation (together with its large-scale variants ChIP-on-chip and ChIP-seq) fluorescent in situ hybridization methylation-sensitive restriction enzymes DNA adenine methyltransferase identification (DamID) and bisulfite sequencing. Furthermore the use of bioinformatic methods is playing an increasing role (computational epigenetics). Mechanisms
Several types of epigenetic inheritance systems may play a role in what has become known as cell memory:10 DNA methylation and chromatin remodeling DNA associates with histone proteins to form chromatin.
Because the phenotype of a cell or individual is affected by which of its genes are transcribed heritable transcription states can give rise to epigenetic effects. There are several layers of regulation of gene expression. One way that genes are regulated is through the remodeling of chromatin. Chromatin is the complex of DNA and the histone proteins with which it associates. Histone proteins are little spheres that DNA wraps around. If the way that DNA is wrapped around the histones changes gene expression can change as well. Chromatin remodeling is accomplished through two main mechanisms: The first way is post translational modification of the amino acids that make up histone proteins. Histone proteins are made up of long chains of amino acids. If the amino acids that are in the chain are changed the shape of the histone sphere might be modified. DNA is not completely unwound during replication. It is possible then that the modified histones may be carried into each new copy of the DNA. Once there these histones may act as templates initiating the surrounding new histones to be shaped in the new manner. By altering the shape of the histones around it these modified histones would ensure that a differentiated cell would stay differentiated and not convert back into being a stem cell. The second way is the addition of methyl groups to the DNA mostly at CpG sites to convert cytosine to 5-methylcytosine. 5-Methylcytosine performs much like a regular cytosine pairing up with a guanine. However some areas of genome are methylated more heavily than others and highly methylated areas tend to be less transcriptionally active through a mechanism not fully understood. Methylation of cytosines can also persist from the germ line of one of the parents into the zygote marking the chromosome as being inherited from this parent (genetic imprinting).
The way that the cells stay dif
Epigenetic was also used by the psychologist Erik Erikson in his Psychosocial development theory. That usage however is of primarily historical interest.8 Molecular basis of epigenetics
The molecular basis of epigenetics is complex. It involves modifications of the activation of certain genes but not the basic structure of DNA. Additionally the chromatin proteins associated with DNA may be activated or silenced. This accounts for why the differentiated cells in a multi-cellular organism express only the genes that are necessary for their own activity. Epigenetic changes are preserved when cells divide. Most epigenetic changes only occur within the course of one individual organism's lifetime but if a mutation in the DNA has been caused in sperm or egg cell that results in fertilization then some epigenetic changes are inherited from one generation to the next.9 This raises the question of whether or not epigenetic changes in an organism can alter the basic structure of its DNA (see Evolution below) a form of Lamarckism.
Specific epigenetic processes include paramutation bookmarking imprinting gene silencing X chromosome inactivation position effect reprogramming transvection maternal effects the progress of carcinogenesis many effects of teratogens regulation of histone modifications and heterochromatin and technical limitations affecting parthenogenesis and cloning.
Epigenetic research uses a wide range of molecular biologic techniques to further our understanding of epigenetic phenomena including chromatin immunoprecipitation (together with its large-scale variants ChIP-on-chip and ChIP-seq) fluorescent in situ hybridization methylation-sensitive restriction enzymes DNA adenine methyltransferase identification (DamID) and bisulfite sequencing. Furthermore the use of bioinformatic methods is playing an increasing role (computational epigenetics). Mechanisms
Several types of epigenetic inheritance systems may play a role in what has become known as cell memory:10 DNA methylation and chromatin remodeling DNA associates with histone proteins to form chromatin.
Because the phenotype of a cell or individual is affected by which of its genes are transcribed heritable transcription states can give rise to epigenetic effects. There are several layers of regulation of gene expression. One way that genes are regulated is through the remodeling of chromatin. Chromatin is the complex of DNA and the histone proteins with which it associates. Histone proteins are little spheres that DNA wraps around. If the way that DNA is wrapped around the histones changes gene expression can change as well. Chromatin remodeling is accomplished through two main mechanisms: The first way is post translational modification of the amino acids that make up histone proteins. Histone proteins are made up of long chains of amino acids. If the amino acids that are in the chain are changed the shape of the histone sphere might be modified. DNA is not completely unwound during replication. It is possible then that the modified histones may be carried into each new copy of the DNA. Once there these histones may act as templates initiating the surrounding new histones to be shaped in the new manner. By altering the shape of the histones around it these modified histones would ensure that a differentiated cell would stay differentiated and not convert back into being a stem cell. The second way is the addition of methyl groups to the DNA mostly at CpG sites to convert cytosine to 5-methylcytosine. 5-Methylcytosine performs much like a regular cytosine pairing up with a guanine. However some areas of genome are methylated more heavily than others and highly methylated areas tend to be less transcriptionally active through a mechanism not fully understood. Methylation of cytosines can also persist from the germ line of one of the parents into the zygote marking the chromosome as being inherited from this parent (genetic imprinting).
The way that the cells stay dif
UK, China Research Teams Partner on $31M Epigenetics Study
NEW YORK (GenomeWeb News) – Research teams in the UK and China have launched a new £20 million ($30.7 million) partnership to study epigenetic factors in thousands of pairs of twins in order to learn why many identical twins do not develop the same diseases as one another, King's College London said today.
NEW YORK (GenomeWeb News) – Research teams in the UK and China have launched a new £20 million ($30.7 million) partnership to study epigenetic factors in thousands of pairs of twins in order to learn why many identical twins do not develop the same diseases as one another, King's College London said today.
we are using amphibian eggs as a starting material for the re programming of adult mammalian cells to pluripotency Epigenetic marks are removed from Nuclei after treatments in extracts Histone H3 Lysine 9 K9 methylation staining of mouse foetal fibroblasts incubated in extracts for 3 hs Green Fitc anti H3H9 antibody Blue DAPI Two central issues underlie the problem of
http://www.nottingham.ac.uk/genetics/people/johnson/research.php?S=&ID=73&pubID=ODAxMDI4
Backgrounder: Epigenetics and Imprinted Genes
Epigenetic modifications include addition of molecules, like methyl groups, to the DNA backbone. ... There are different kinds of epigenetic "marks," chemical additions to the ...
Epigenetic modifications include addition of molecules, like methyl groups, to the DNA backbone. ... There are different kinds of epigenetic "marks," chemical additions to the ...
ferentiated in the case of DNA methylation is clearer to us than it is in the case of histone shape. Basically certain enzymes (such as DNMT1) have a higher affinity for the methylated cytosine. If this enzyme reaches a "hemimethylated" portion of DNA (where methylcytosine is in only one of the two DNA strands) the enzyme will methylate the other half.
Although histone modifications occur throughout the entire sequence the unstructured N-termini of histones (called histone tails) are particularly highly modified. These modifications include acetylation methylation ubiquitylation phosphorylation and sumoylation. Acetylation is the most highly studied of these modifications. For example acetylation of the K14 and K9 lysines of the tail of histone H3 by histone acetyltransferase enzymes (HATs) is generally correlated with transcriptional competence.
One mode of thinking is that this tendency of acetylation to be associated with "active" transcription is biophysical in nature. Because it normally has a positively charged nitrogen at its end lysine can bind the negatively charged phosphates of the DNA backbone and prevent them from repelling each other. The acetylation event converts the positively charged amine group on the side chain into a neutral amide linkage. This removes the positive charge causing the DNA to repel itself. When this occurs complexes like SWI/SNF and other transcriptional factors can bind to the DNA thus opening it up and exposing it to enzymes like RNA polymerase so transcription of the gene can occur.
In addition the positively charged tails of histone proteins from one nucleosome may interact with the histone proteins on a neighboring nucleosome causing them to pack closely. Lysine acetylation may interfere with these interactions causing the chromatin structure to open up.
Lysine acetylation may also act as a beacon to recruit other activating chromatin modifying enzymes (and basal transcription machinery as well). Indeed the bromodomain a protein segment (domain) that specifically binds acetyl-lysine is found in many enzymes that help activate transcription including the SWI/SNF complex (on the protein polybromo). It may be that acetylation acts in this and the previous way to aid in transcriptional activation.
The idea that modifications act as docking modules for related factors is borne out by histone methylation as well. Methylation of lysine 9 of histone H3 has long been associated with constitutively transcriptionally silent chromatin (constitutive heterochromatin). It has been determined that a chromodomain (a domain that specifically binds methyl-lysine) in the transcriptionally repressive protein HP1 recruits HP1 to K9 methylated regions. One example that seems to refute this biophysical model for acetylation is that tri-methylation of histone H3 at lysine 4 is strongly associated with (and required for full) transcriptional activation. Tri-methylation in this case would introduce a fixed positive charge on the tail.
It should be emphasized that differing histone modifications are likely to function in differing ways; acetylation at one position is likely to function differently than acetylation at another position. Also multiple modifications may occur at the same time and these modifications may work together to change the behavior of the nucleosome. The idea that multiple dynamic modifications regulate gene transcription in a systematic and reproducible way is called the histone code.
DNA methylation frequently occurs in repeated sequences and helps to suppress the expression and mobility of 'transposable elements':11 Because 5-methylcytosine is chemically very similar to thymidine CpG sites are frequently mutated and become rare in the genome except at CpG islands where they remain unmethylated. Epigenetic changes of this type thus have the potential to direct increased frequencies of permanent genetic mutation. DNA methylation patterns are known to be established and modified in response to environmental factors by a complex interplay of at least three independent DNA methyltransferases DNMT1 DNMT3A and DNMT3B the loss of any of which is lethal in mice.12 DNMT1 is the most abundant methyltransferase in somatic cells13 localizes to replication foci14 has a 1040-fold preference for hemimethylated DNA and interacts with the proliferating cell nuclear antigen (PCNA).15 By preferentially modifying hemimethylated DNA DNMT1 transfers patterns of methylation to a new
Although histone modifications occur throughout the entire sequence the unstructured N-termini of histones (called histone tails) are particularly highly modified. These modifications include acetylation methylation ubiquitylation phosphorylation and sumoylation. Acetylation is the most highly studied of these modifications. For example acetylation of the K14 and K9 lysines of the tail of histone H3 by histone acetyltransferase enzymes (HATs) is generally correlated with transcriptional competence.
One mode of thinking is that this tendency of acetylation to be associated with "active" transcription is biophysical in nature. Because it normally has a positively charged nitrogen at its end lysine can bind the negatively charged phosphates of the DNA backbone and prevent them from repelling each other. The acetylation event converts the positively charged amine group on the side chain into a neutral amide linkage. This removes the positive charge causing the DNA to repel itself. When this occurs complexes like SWI/SNF and other transcriptional factors can bind to the DNA thus opening it up and exposing it to enzymes like RNA polymerase so transcription of the gene can occur.
In addition the positively charged tails of histone proteins from one nucleosome may interact with the histone proteins on a neighboring nucleosome causing them to pack closely. Lysine acetylation may interfere with these interactions causing the chromatin structure to open up.
Lysine acetylation may also act as a beacon to recruit other activating chromatin modifying enzymes (and basal transcription machinery as well). Indeed the bromodomain a protein segment (domain) that specifically binds acetyl-lysine is found in many enzymes that help activate transcription including the SWI/SNF complex (on the protein polybromo). It may be that acetylation acts in this and the previous way to aid in transcriptional activation.
The idea that modifications act as docking modules for related factors is borne out by histone methylation as well. Methylation of lysine 9 of histone H3 has long been associated with constitutively transcriptionally silent chromatin (constitutive heterochromatin). It has been determined that a chromodomain (a domain that specifically binds methyl-lysine) in the transcriptionally repressive protein HP1 recruits HP1 to K9 methylated regions. One example that seems to refute this biophysical model for acetylation is that tri-methylation of histone H3 at lysine 4 is strongly associated with (and required for full) transcriptional activation. Tri-methylation in this case would introduce a fixed positive charge on the tail.
It should be emphasized that differing histone modifications are likely to function in differing ways; acetylation at one position is likely to function differently than acetylation at another position. Also multiple modifications may occur at the same time and these modifications may work together to change the behavior of the nucleosome. The idea that multiple dynamic modifications regulate gene transcription in a systematic and reproducible way is called the histone code.
DNA methylation frequently occurs in repeated sequences and helps to suppress the expression and mobility of 'transposable elements':11 Because 5-methylcytosine is chemically very similar to thymidine CpG sites are frequently mutated and become rare in the genome except at CpG islands where they remain unmethylated. Epigenetic changes of this type thus have the potential to direct increased frequencies of permanent genetic mutation. DNA methylation patterns are known to be established and modified in response to environmental factors by a complex interplay of at least three independent DNA methyltransferases DNMT1 DNMT3A and DNMT3B the loss of any of which is lethal in mice.12 DNMT1 is the most abundant methyltransferase in somatic cells13 localizes to replication foci14 has a 1040-fold preference for hemimethylated DNA and interacts with the proliferating cell nuclear antigen (PCNA).15 By preferentially modifying hemimethylated DNA DNMT1 transfers patterns of methylation to a new
TwinsUK and BGI to Study Epigenetics of 5,000 Twins under $30M Project
TwinsUK and Chinese genome institute BGI have launched a $30 million project called Epitwin to study epigenetic differences in 5,000 twins, the organizations said this week.
TwinsUK and Chinese genome institute BGI have launched a $30 million project called Epitwin to study epigenetic differences in 5,000 twins, the organizations said this week.
the human race and controlling human diseases 6Epigenetics is the study of heritable changes in gene function that occur without a change in the DNA sequence Epigenetic mechanisms includes histone modification DNA methylation replacing H with CH3 and RNA interference DNA methylation is to add a methyl group to the DNA frequently to the base cytosine when it is
http://universe-review.ca/F11-monocell.htm
Epigenetics | Book
The molecular mechanisms and biological processes in which epigenetic modifications play a primordial role are described in detail.
The molecular mechanisms and biological processes in which epigenetic modifications play a primordial role are described in detail.
ly synthesized strand after DNA replication and therefore is often referred to as the maintenance' methyltransferase.16 DNMT1 is essential for proper embryonic development imprinting and X-inactivation.1217
Chromosomal regions can adopt stable and heritable alternative states resulting in bistable gene expression without changes to the DNA sequence. Epigenetic control is often associated with alternative covalent modifications of histones18. The stability and heritability of states of larger chromosomal regions are often thought to involve positive feedback where modified nucleosomes recruit enzymes that similarly modify nearby nucleosomes. A simplified stochastic model for this type of epigenetics is found here 19 .
Because DNA methylation and chromatin remodeling play such a central role in many types of epigenic inheritance the word "epigenetics" is sometimes used as a synonym for these processes. However this can be misleading. Chromatin remodeling is not always inherited and not all epigenetic inheritance involves chromatin remodeling.20
It has been suggested that the histone code could be mediated by the effect of small RNAs. The recent discovery and characterization of a vast array of small (21- to 26-nt) non-coding RNAs suggests that there is an RNA component possibly involved in epigenetic gene regulation. Small interfering RNAs can modulate transcriptional gene expression via epigenetic modulation of targeted promoters.21 RNA transcripts and their encoded proteins
Sometimes a gene after being turned on transcribes a product that (either directly or indirectly) maintains the activity of that gene. For example Hnf4 and MyoD enhance the transcription of many liver- and muscle-specific genes respectively including their own through the transcription factor activity of the proteins they encode. RNA signalling includes differential recruitment of a hierarchy of generic chromatin modifying complexes and DNA methyltransferases to specific loci by RNAs during differentiation and development22. Other epigenetic changes are mediated by the production of different splice forms of RNA or by formation of double-stranded RNA (RNAi). Descendants of the cell in which the gene was turned on will inherit this activity even if the original stimulus for gene-activation is no longer present. These genes are most often turned on or off by signal transduction although in some systems where syncytia or gap junctions are important RNA may spread directly to other cells or nuclei by diffusion. A large amount of RNA and protein is contributed to the zygote by the mother during oogenesis or via nurse cells resulting in maternal effect phenotypes. A smaller quantity of sperm RNA is transmitted from the father but there is recent evidence that this epigenetic information can lead to visible changes in several generations of offspring.23 Prions For more details on this topic see Prions.
Prions are infectious forms of proteins. Proteins generally fold into discrete units which perform distinct cellular functions but some proteins are also capable of forming an infectious conformational state known as a prion. Although often viewed in the context of infectious disease prions are more loosely defined by their ability to catalytically convert other native state versions of the same protein to an infectious conformational state. It is in this latter sense that they can be viewed as epigenetic agents capable of inducing a phenotypic change without a modification of the genome.24
Fungal prions are considered epigenetic because the infectious phenotype caused by the prion can be inherited without modification of the genome. PSI+ and URE3 discovered in yeast in 1965 and 1971 are the two best studied of this type of prion.2526 Prions can have a phenotypic effect through the sequestration of protein in aggregates thereby reducing that protein's activity. In PSI+ cells the loss of the Sup35 protein (which is involved in termination of translation) causes ribosomes to have a higher rate of read-through of stop codons an effect which results in suppression of nonsense mutations in other genes.27 The ability of Sup35 to form prions may be a conserved trait. It could confer an adaptive advantage by giving cells the ability to switch into a PSI+ state and express dormant genetic features normally terminated by premature stop codon mutations.2829 Structural inheritance systems For more details on this topic see Structural inheritance.
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http://biopinionated.com/2008/01/23/a-refreshing-view-on-james-watson
life and it is becoming increasingly apparent that chemicals can cause changes in gene expression that persist long after exposure has ceased Medical Hypotheses June 4 2009 online Mechanisms now understood
http://www.edgeofnowhere.cc/viewtopic.php?t=434368&highlight=
https://musom.marshall.edu/microbiology/sollars/research-interest.htm
Epigenetic vs Syngenetic Permafrost i e Top Down vs Bottom Up Epigenetic permafrost forms as the average annual climate cools down Winters may be colder and last longer summers may be cooler or just shorter Most new permafrost is
http://www.crrel.usace.army.mil/permafrosttunnel/1g2b_Types_of_Permafrost.htm
Colorful chaos today and tomorrow
http://www.colourlovers.com/blog/2009/06/28/eclectic-color-roundup-37
on the road bifurcation points at which energies for change either dissipate and dissolve in a way that allows the old attractor to reassert itself or shift the system into a new form Figure 6 The egg will find its way but which way Note 119 Changes in organizations New initiatives often generate their negation and it is difficult to say whether the solution will
http://www.ebbemunk.dk/technostructure/technostructurep4.html
http://www.hkedcity.net/iworld/plan/view.phtml?iworld_id=54¤t_page=&feature_id=1788&page=2
Chromosomal regions can adopt stable and heritable alternative states resulting in bistable gene expression without changes to the DNA sequence. Epigenetic control is often associated with alternative covalent modifications of histones18. The stability and heritability of states of larger chromosomal regions are often thought to involve positive feedback where modified nucleosomes recruit enzymes that similarly modify nearby nucleosomes. A simplified stochastic model for this type of epigenetics is found here 19 .
Because DNA methylation and chromatin remodeling play such a central role in many types of epigenic inheritance the word "epigenetics" is sometimes used as a synonym for these processes. However this can be misleading. Chromatin remodeling is not always inherited and not all epigenetic inheritance involves chromatin remodeling.20
It has been suggested that the histone code could be mediated by the effect of small RNAs. The recent discovery and characterization of a vast array of small (21- to 26-nt) non-coding RNAs suggests that there is an RNA component possibly involved in epigenetic gene regulation. Small interfering RNAs can modulate transcriptional gene expression via epigenetic modulation of targeted promoters.21 RNA transcripts and their encoded proteins
Sometimes a gene after being turned on transcribes a product that (either directly or indirectly) maintains the activity of that gene. For example Hnf4 and MyoD enhance the transcription of many liver- and muscle-specific genes respectively including their own through the transcription factor activity of the proteins they encode. RNA signalling includes differential recruitment of a hierarchy of generic chromatin modifying complexes and DNA methyltransferases to specific loci by RNAs during differentiation and development22. Other epigenetic changes are mediated by the production of different splice forms of RNA or by formation of double-stranded RNA (RNAi). Descendants of the cell in which the gene was turned on will inherit this activity even if the original stimulus for gene-activation is no longer present. These genes are most often turned on or off by signal transduction although in some systems where syncytia or gap junctions are important RNA may spread directly to other cells or nuclei by diffusion. A large amount of RNA and protein is contributed to the zygote by the mother during oogenesis or via nurse cells resulting in maternal effect phenotypes. A smaller quantity of sperm RNA is transmitted from the father but there is recent evidence that this epigenetic information can lead to visible changes in several generations of offspring.23 Prions For more details on this topic see Prions.
Prions are infectious forms of proteins. Proteins generally fold into discrete units which perform distinct cellular functions but some proteins are also capable of forming an infectious conformational state known as a prion. Although often viewed in the context of infectious disease prions are more loosely defined by their ability to catalytically convert other native state versions of the same protein to an infectious conformational state. It is in this latter sense that they can be viewed as epigenetic agents capable of inducing a phenotypic change without a modification of the genome.24
Fungal prions are considered epigenetic because the infectious phenotype caused by the prion can be inherited without modification of the genome. PSI+ and URE3 discovered in yeast in 1965 and 1971 are the two best studied of this type of prion.2526 Prions can have a phenotypic effect through the sequestration of protein in aggregates thereby reducing that protein's activity. In PSI+ cells the loss of the Sup35 protein (which is involved in termination of translation) causes ribosomes to have a higher rate of read-through of stop codons an effect which results in suppression of nonsense mutations in other genes.27 The ability of Sup35 to form prions may be a conserved trait. It could confer an adaptive advantage by giving cells the ability to switch into a PSI+ state and express dormant genetic features normally terminated by premature stop codon mutations.2829 Structural inheritance systems For more details on this topic see Structural inheritance.
Scientists Discover Gene Mutation Common in a Class of Ovarian Cancers
A study of aggressive ovarian tumors has revealed a new class of major cancer-driving mutations. Howard Hughes Medical Institute (HHMI) researchers found that most of the clear cell ovarian carcinoma samples they studied carried a gene mutation that alters the epigenetics of cells.
A study of aggressive ovarian tumors has revealed a new class of major cancer-driving mutations. Howard Hughes Medical Institute (HHMI) researchers found that most of the clear cell ovarian carcinoma samples they studied carried a gene mutation that alters the epigenetics of cells.
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http://biopinionated.com/2008/01/23/a-refreshing-view-on-james-watson
Epigenetics - Psychology Wiki
Epigenetics is the study of epigenetic inheritance, a set of reversible heritable changes in gene function or other cell phenotype that occur without ...
Epigenetics is the study of epigenetic inheritance, a set of reversible heritable changes in gene function or other cell phenotype that occur without ...
/>In ciliates such as Tetrahymena and Paramecium genetically identical cells show heritable differences in the patterns of ciliary rows on their cell surface. Experimentally altered patterns can be transmitted to daughter cells. It seems existing structures act as templates for new structures. The mechanisms of such inheritance are unclear but reasons exist to assume that multicellular organisms also use existing cell structures to assemble new ones.30
Functions and consequences
Development
Somatic epigenetic inheritance particularly through DNA methylation and chromatin remodeling is very important in the development of multicellular eukaryotic organisms. The genome sequence is static (with some notable exceptions) but cells differentiate into many different types which perform different functions and respond differently to the environment and intercellular signalling. Thus as individuals develop morphogens activate or silence genes in an epigenetically heritable fashion giving cells a "memory". In mammals most cells terminally differentiate with only stem cells retaining the ability to differentiate into several cell types ("totipotency" and "multipotency"). In mammals some stem cells continue producing new differentiated cells throughout life but mammals are not able to respond to loss of some tissues for example the inability to regenerate limbs which some other animals are capable of. Unlike animals plant cells do not terminally differentiate remaining totipotent with the ability to give rise to a new individual plant. While plants do utilise many of the same epigenetic mechanisms as animals such as chromatin remodeling it has been hypothesised that plant cells do not have "memories" resetting their gene expression patterns at each cell division using positional information from the environment and surrounding cells to determine their fate.31 Medicine
Epigenetics has many and varied potential medical applications. Congenital genetic disease is well understood and it is also clear that epigenetics can play a role for example in the case of Angelman syndrome and Prader-Willi syndrome. These are normal genetic diseases caused by gene deletions or inactivation of the genes but are unusually common because individuals are essentially hemizygous because of genomic imprinting and therefore a single gene knock out is sufficient to cause the disease where most cases would require both copies to be knocked out.32 Evolution
Although epigenetics in multicellular organisms is generally thought to be a mechanism involved in differentiation with epigenetic patterns "reset" when organisms reproduce there have been some observations of transgenerational epigenetic inheritance (e.g. the phenomenon of paramutation observed in maize). Although most of these multigenerational epigenetic traits are gradually lost over several generations the possibility remains that multigenerational epigenetics could be another aspect to evolution and adaptation. A sequestered germ line or Weismann barrier is specific to animals and epigenetic inheritance is expected to be far more common in plants and microbes. These effects may require enhancements to the standard conceptual framework of the modern evolutionary synthesis.3334
Epigenetic features may play a role in short-term adaptation of species by allowing for reversible phenotype variability. The modification of epigenetic features associated with a region of DNA allows organisms on a multigenerational time scale to switch between phenotypes that express and repress that particular gene.35 When the DNA sequence of the region is not mutated this change is reversible. It has also been speculated that organisms may take advantage of differential mutation rates associated with epigenetic features to control the mutation rates of particular genes.35
Epigenetic changes have also been observed to occur in response to environmental exposurefor example mice given some dietary supplements have epigenetic changes affecting expression of the agouti gene which affects their fur color weight and propensity to develop cancer.3637 Transgenerational epigenetic observations
A comprehensive review of over 100 cases of transgenerational epigenetic inheritance reported the phenomena in a wide range of organisms including prokaryotes plants and animals. 38 Epigenetic effects in humans Genomic imprinting and related disorders
Some human disorders are associated with genomic imprinting a phe
Somatic epigenetic inheritance particularly through DNA methylation and chromatin remodeling is very important in the development of multicellular eukaryotic organisms. The genome sequence is static (with some notable exceptions) but cells differentiate into many different types which perform different functions and respond differently to the environment and intercellular signalling. Thus as individuals develop morphogens activate or silence genes in an epigenetically heritable fashion giving cells a "memory". In mammals most cells terminally differentiate with only stem cells retaining the ability to differentiate into several cell types ("totipotency" and "multipotency"). In mammals some stem cells continue producing new differentiated cells throughout life but mammals are not able to respond to loss of some tissues for example the inability to regenerate limbs which some other animals are capable of. Unlike animals plant cells do not terminally differentiate remaining totipotent with the ability to give rise to a new individual plant. While plants do utilise many of the same epigenetic mechanisms as animals such as chromatin remodeling it has been hypothesised that plant cells do not have "memories" resetting their gene expression patterns at each cell division using positional information from the environment and surrounding cells to determine their fate.31 Medicine
Epigenetics has many and varied potential medical applications. Congenital genetic disease is well understood and it is also clear that epigenetics can play a role for example in the case of Angelman syndrome and Prader-Willi syndrome. These are normal genetic diseases caused by gene deletions or inactivation of the genes but are unusually common because individuals are essentially hemizygous because of genomic imprinting and therefore a single gene knock out is sufficient to cause the disease where most cases would require both copies to be knocked out.32 Evolution
Although epigenetics in multicellular organisms is generally thought to be a mechanism involved in differentiation with epigenetic patterns "reset" when organisms reproduce there have been some observations of transgenerational epigenetic inheritance (e.g. the phenomenon of paramutation observed in maize). Although most of these multigenerational epigenetic traits are gradually lost over several generations the possibility remains that multigenerational epigenetics could be another aspect to evolution and adaptation. A sequestered germ line or Weismann barrier is specific to animals and epigenetic inheritance is expected to be far more common in plants and microbes. These effects may require enhancements to the standard conceptual framework of the modern evolutionary synthesis.3334
Epigenetic features may play a role in short-term adaptation of species by allowing for reversible phenotype variability. The modification of epigenetic features associated with a region of DNA allows organisms on a multigenerational time scale to switch between phenotypes that express and repress that particular gene.35 When the DNA sequence of the region is not mutated this change is reversible. It has also been speculated that organisms may take advantage of differential mutation rates associated with epigenetic features to control the mutation rates of particular genes.35
Epigenetic changes have also been observed to occur in response to environmental exposurefor example mice given some dietary supplements have epigenetic changes affecting expression of the agouti gene which affects their fur color weight and propensity to develop cancer.3637 Transgenerational epigenetic observations
A comprehensive review of over 100 cases of transgenerational epigenetic inheritance reported the phenomena in a wide range of organisms including prokaryotes plants and animals. 38 Epigenetic effects in humans Genomic imprinting and related disorders
Some human disorders are associated with genomic imprinting a phe
Is meat and milk from clones in the food supply?
It’s just a matter of time before we are eating clones, if we are not eating them now.
It’s just a matter of time before we are eating clones, if we are not eating them now.
life and it is becoming increasingly apparent that chemicals can cause changes in gene expression that persist long after exposure has ceased Medical Hypotheses June 4 2009 online Mechanisms now understood
http://www.edgeofnowhere.cc/viewtopic.php?t=434368&highlight=
epigenetic - definition of epigenetic by the Free Online ...
Translations of epigenetic. epigenetic synonyms, epigenetic antonyms. Information about epigenetic in the free online English dictionary and ...
Translations of epigenetic. epigenetic synonyms, epigenetic antonyms. Information about epigenetic in the free online English dictionary and ...
nomenon in mammals where the father and mother contribute different epigenetic patterns for specific genomic loci in their germ cells.39 The best-known case of imprinting in human disorders is that of Angelman syndrome and Prader-Willi syndromeboth can be produced by the same genetic mutation chromosome 15q partial deletion and the particular syndrome that will develop depends on whether the mutation is inherited from the child's mother or from their father.40 This is due to the presence of genomic imprinting in the region. Beckwith-Wiedemann syndrome is also associated with genomic imprinting often caused by abnormalities in maternal genomic imprinting of a region on chromosome 11.
Transgenerational epigenetic observations
Marcus Pembrey and colleagues also observed in the verkalix study that the paternal (but not maternal) grandsons of Swedish boys who were exposed during preadolescence to famine in the 19th century were less likely to die of cardiovascular disease; if food was plentiful then diabetes mortality in the grandchildren increased suggesting that this was a transgenerational epigenetic inheritance.41 The opposite effect was observed for females -- the paternal (but not maternal) granddaughters of women who experienced famine while in the womb (and their eggs were being formed) lived shorter lives on average.42 Cancer and developmental abnormalities
A variety of compounds are considered as epigenetic carcinogensthey result in an increased incidence of tumors but they do not show mutagen activity (toxic compounds or pathogens that cause tumors incident to increased regeneration should also be excluded). Examples include diethylstilbestrol arsenite hexachlorobenzene and nickel compounds.
Many teratogens exert specific effects on the fetus by epigenetic mechanisms.4344 While epigenetic effects may preserve the effect of a teratogen such as diethylstilbestrol throughout the life of an affected child the possibility of birth defects resulting from exposure of fathers or in second and succeeding generations of offspring has generally been rejected on theoretical grounds and for lack of evidence.45 However a range of male-mediated abnormalities have been demonstrated and more are likely to exist.46 FDA label information for Vidaza(tm) a formulation of 5-azacitidine (an unmethylatable analog of cytidine that causes hypomethylation when incorporated into DNA) states that "men should be advised not to father a child" while using the drug citing evidence in treated male mice of reduced fertility increased embryo loss and abnormal embryo development. In rats endocrine differences were observed in offspring of males exposed to morphine.47 In mice second generation effects of diethylstilbesterol have been described occurring by epigenetic mechanisms.48 In 2008 the National Institutes of Health announced that $190 million had been earmarked for epigenetics research over the next five years. In announcing the funding government officials noted that epigenetics has the potential to explain mechanisms of aging human development and the origins of cancer heart disease mental illness as well as several other conditions. Some investigators like Randy Jirtle PhD of Duke University Medical Center think epigenetics may ultimately turn out to have a greater role in disease than genetics.49 Twin studies
Recent studies involving both dizygotic and monozygotic twins have produced some evidence of epigenetic influence in humans.505152 Epigenetics in microorganisms
Bacteria make widespread use of postreplicative DNA methylation for the epigenetic control of DNA-protein interactions. Bacteria make use of DNA adenine methylation (rather than DNA cytosine methylation) as an epigenetic signal. DNA adenine methylation is important in bacteria virulence in organisms such as Escherichia coli Salmonella Vibrio Yersinia Haemophilus and Brucella. In Alphaproteobacteria methylation of adenine regulates the cell cycle and couples gene transcription to DNA replication. In Gammaproteobacteria adenine methylation provides signals for DNA replication chromosome segregation mismatch repair packaging of bacteriophage transposase activity and regulation of gene expression.5354
The filamentous fungus Neurospora crassa is a prominent model system for understanding the control and function of cytosine methylation. In this organisms DNA methylation is associated with relics of a genome defense system called RIP (repeat-induced point mutat
Marcus Pembrey and colleagues also observed in the verkalix study that the paternal (but not maternal) grandsons of Swedish boys who were exposed during preadolescence to famine in the 19th century were less likely to die of cardiovascular disease; if food was plentiful then diabetes mortality in the grandchildren increased suggesting that this was a transgenerational epigenetic inheritance.41 The opposite effect was observed for females -- the paternal (but not maternal) granddaughters of women who experienced famine while in the womb (and their eggs were being formed) lived shorter lives on average.42 Cancer and developmental abnormalities
A variety of compounds are considered as epigenetic carcinogensthey result in an increased incidence of tumors but they do not show mutagen activity (toxic compounds or pathogens that cause tumors incident to increased regeneration should also be excluded). Examples include diethylstilbestrol arsenite hexachlorobenzene and nickel compounds.
Many teratogens exert specific effects on the fetus by epigenetic mechanisms.4344 While epigenetic effects may preserve the effect of a teratogen such as diethylstilbestrol throughout the life of an affected child the possibility of birth defects resulting from exposure of fathers or in second and succeeding generations of offspring has generally been rejected on theoretical grounds and for lack of evidence.45 However a range of male-mediated abnormalities have been demonstrated and more are likely to exist.46 FDA label information for Vidaza(tm) a formulation of 5-azacitidine (an unmethylatable analog of cytidine that causes hypomethylation when incorporated into DNA) states that "men should be advised not to father a child" while using the drug citing evidence in treated male mice of reduced fertility increased embryo loss and abnormal embryo development. In rats endocrine differences were observed in offspring of males exposed to morphine.47 In mice second generation effects of diethylstilbesterol have been described occurring by epigenetic mechanisms.48 In 2008 the National Institutes of Health announced that $190 million had been earmarked for epigenetics research over the next five years. In announcing the funding government officials noted that epigenetics has the potential to explain mechanisms of aging human development and the origins of cancer heart disease mental illness as well as several other conditions. Some investigators like Randy Jirtle PhD of Duke University Medical Center think epigenetics may ultimately turn out to have a greater role in disease than genetics.49 Twin studies
Recent studies involving both dizygotic and monozygotic twins have produced some evidence of epigenetic influence in humans.505152 Epigenetics in microorganisms
Bacteria make widespread use of postreplicative DNA methylation for the epigenetic control of DNA-protein interactions. Bacteria make use of DNA adenine methylation (rather than DNA cytosine methylation) as an epigenetic signal. DNA adenine methylation is important in bacteria virulence in organisms such as Escherichia coli Salmonella Vibrio Yersinia Haemophilus and Brucella. In Alphaproteobacteria methylation of adenine regulates the cell cycle and couples gene transcription to DNA replication. In Gammaproteobacteria adenine methylation provides signals for DNA replication chromosome segregation mismatch repair packaging of bacteriophage transposase activity and regulation of gene expression.5354
The filamentous fungus Neurospora crassa is a prominent model system for understanding the control and function of cytosine methylation. In this organisms DNA methylation is associated with relics of a genome defense system called RIP (repeat-induced point mutat
Researchers identify genes tied to deadliest ovarian cancers
( Johns Hopkins Medical Institutions ) Scientists at the Johns Hopkins Kimmel Cancer Center have identified two genes whose mutations appear to be linked to ovarian clear cell carcinoma, one of the most aggressive forms of ovarian cancer. Clear cell carcinoma is generally resistant to standard therapy.
( Johns Hopkins Medical Institutions ) Scientists at the Johns Hopkins Kimmel Cancer Center have identified two genes whose mutations appear to be linked to ovarian clear cell carcinoma, one of the most aggressive forms of ovarian cancer. Clear cell carcinoma is generally resistant to standard therapy.
https://musom.marshall.edu/microbiology/sollars/research-interest.htm
Epigenetic | Define Epigenetic at Dictionary.com
Epigenetic definition, the theory that an embryo develops from the successive differentiation of an originally undifferentiated structure ( See more.
Epigenetic definition, the theory that an embryo develops from the successive differentiation of an originally undifferentiated structure ( See more.
ion) and silences gene expression by inhibiting transcription elongation.55
The yeast prion PSI is generated by a conformational change of a translation termination factor which is then inherited by daughter cells. This can provide a survival advantage under adverse conditions. This is an example of epigenetic regulation enabling unicellular organisms to respond rapidly to environmental stress. Prions can be viewed as epigenetic agents capable of inducing a phenotypic change without modification of the genome.54 See also B chromosome Epigenetic Theory Baldwin effect Centromere Computational epigenetics Dutch famine of 1944 (scientific legacy) Evolutionary developmental psychology Emergenesis Histone code Human genome Molecular biology Preformationism Somatic epitype Synthetic genetic array Weismann barrier Further reading Oskar Hertwig 18491922 (1896). Biological problem of today: preformation or epigenesis The basis of a theory of organic development. London: W. Heinemann. Jaenisch R; Bird A (March 2003). "Epigenetic regulation of gene expression: how the genome integrates intrinsic and environmental signals". Nat. Genet. 33 (Suppl): 24554. doi:10.1038/ng1089. PMID 12610534. Lederberg J (September 17 2001). "The Meaning of Epigenetics". The Scientist 15 (18): 6. Sims RJ Nishioka K Reinberg D (November 2003). "Histone lysine methylation: a signature for chromatin function". Trends Genet. 19 (11): 62939. doi:10.1016/j.tig.2003.09.007. PMID 14585615. http://linkinghub.elsevier.com/retrieve/pii/S0168952503002610. Strahl BD Allis CD (January 2000). "The language of covalent histone modifications". Nature 403 (6765): 415. doi:10.1038/47412. PMID 10638745. Waddington CH (1942). "The epigenotype". Endeavour 1: 1820. McClintock B (1978). "Mechanisms that Rapidly Reorganize the Genome". Stadler Symposium 10: 2548. Karl J. Aufderheide; Gary W. Grimes (1991). Cellular aspects of pattern formation: the problem of assembly. Monographs in Developmental Biology. 22. Basel New York: Karger. ISBN 3-8055-5382-X. Lamb Marion J.; Jablonka Eva (2005). Evolution in four dimensions: genetic epigenetic behavioral and symbolic variation in the history of life. Cambridge Mass: MIT Press. ISBN 0-262-10107-6. Article on The Philosophy of Molecular and Developmental Biology to appear in Blackwells Guide to Philosophy of Science. P.K. Machamer and M. Silberstein (Eds). 'Reinberg Danny; Allis C. David; Jenuwein Thomas (2007). Epigenetics. Plainview N.Y: Cold Spring Harbor Laboratory Press. ISBN 0-87969-724-5. Nipam H. Patel; Barton Nicholas John; Derek E. G. Briggs; Eisen Jonathan; Goldstein David I. (2007). Evolution. Plainview N.Y: Cold Spring Harbor Laboratory Press. ISBN 0-87969-684-2. Turner Bryan S. (2001). Chromatin and gene regulation: mechanisms in epigenetics. Oxford: Blackwell Science. ISBN 0-86542-743-7. Jorg Tost (2008). Epigenetics. Norfolk England: Caister Academic Press. ISBN 1-904455-23-9. http://www.horizonpress.com/epi. Morris Kevin L. (2008). RNA and the Regulation of Gene Expression: A Hidden Layer of Complexity. Norfolk England: Caister Academic Press. ISBN 1-904455-25-5. http://www.horizonpress.com/rnareg. Peedicayil J (November 2008). "Epigenetic biomarkers in psychiatric disorders". Br. J. Pharmacol. 155 (6): 7956. doi:10.1038/bjp.2008.254. PMID 18574461. Notes and references Adrian Bird (2007). "Perceptions of epigenetics". Nature 447 (7143): 396398. doi:10.1038/nature05913. PMID 17522671. PMID 17522671 Special report: 'What genes remember' by Philip Hunter Prospect Magazine May 2008 issue 146 Reik Wolf (2007-05-23). "Stability and flexibility of epigenetic gene regulation in mammalian development". Nature 447 (May (online)): 425432. doi:10.1038/nature05918. http://www.nature.com/nature/journal/v447/n7143/full/nature05918.html. Retrieved 2008-04-05. C.H. Waddington (1942) (1977). "The epigenotype". Endeavour 1: 1820. doi:10.1016/0160-9327(77)90005-9. According to the Oxford English Dictionary: The word is used by W. Harvey Exercitationes 1651 p. 148 and in the English Anatomical Exercitations 1653 p. 272. It is explained to mean partium super-exorientium additamentum the additament of parts budding one out of another. It is also worth quoting this adumbration of the definition given there (viz. "The formation of an organic germ as a new product"): t
The yeast prion PSI is generated by a conformational change of a translation termination factor which is then inherited by daughter cells. This can provide a survival advantage under adverse conditions. This is an example of epigenetic regulation enabling unicellular organisms to respond rapidly to environmental stress. Prions can be viewed as epigenetic agents capable of inducing a phenotypic change without modification of the genome.54 See also B chromosome Epigenetic Theory Baldwin effect Centromere Computational epigenetics Dutch famine of 1944 (scientific legacy) Evolutionary developmental psychology Emergenesis Histone code Human genome Molecular biology Preformationism Somatic epitype Synthetic genetic array Weismann barrier Further reading Oskar Hertwig 18491922 (1896). Biological problem of today: preformation or epigenesis The basis of a theory of organic development. London: W. Heinemann. Jaenisch R; Bird A (March 2003). "Epigenetic regulation of gene expression: how the genome integrates intrinsic and environmental signals". Nat. Genet. 33 (Suppl): 24554. doi:10.1038/ng1089. PMID 12610534. Lederberg J (September 17 2001). "The Meaning of Epigenetics". The Scientist 15 (18): 6. Sims RJ Nishioka K Reinberg D (November 2003). "Histone lysine methylation: a signature for chromatin function". Trends Genet. 19 (11): 62939. doi:10.1016/j.tig.2003.09.007. PMID 14585615. http://linkinghub.elsevier.com/retrieve/pii/S0168952503002610. Strahl BD Allis CD (January 2000). "The language of covalent histone modifications". Nature 403 (6765): 415. doi:10.1038/47412. PMID 10638745. Waddington CH (1942). "The epigenotype". Endeavour 1: 1820. McClintock B (1978). "Mechanisms that Rapidly Reorganize the Genome". Stadler Symposium 10: 2548. Karl J. Aufderheide; Gary W. Grimes (1991). Cellular aspects of pattern formation: the problem of assembly. Monographs in Developmental Biology. 22. Basel New York: Karger. ISBN 3-8055-5382-X. Lamb Marion J.; Jablonka Eva (2005). Evolution in four dimensions: genetic epigenetic behavioral and symbolic variation in the history of life. Cambridge Mass: MIT Press. ISBN 0-262-10107-6. Article on The Philosophy of Molecular and Developmental Biology to appear in Blackwells Guide to Philosophy of Science. P.K. Machamer and M. Silberstein (Eds). 'Reinberg Danny; Allis C. David; Jenuwein Thomas (2007). Epigenetics. Plainview N.Y: Cold Spring Harbor Laboratory Press. ISBN 0-87969-724-5. Nipam H. Patel; Barton Nicholas John; Derek E. G. Briggs; Eisen Jonathan; Goldstein David I. (2007). Evolution. Plainview N.Y: Cold Spring Harbor Laboratory Press. ISBN 0-87969-684-2. Turner Bryan S. (2001). Chromatin and gene regulation: mechanisms in epigenetics. Oxford: Blackwell Science. ISBN 0-86542-743-7. Jorg Tost (2008). Epigenetics. Norfolk England: Caister Academic Press. ISBN 1-904455-23-9. http://www.horizonpress.com/epi. Morris Kevin L. (2008). RNA and the Regulation of Gene Expression: A Hidden Layer of Complexity. Norfolk England: Caister Academic Press. ISBN 1-904455-25-5. http://www.horizonpress.com/rnareg. Peedicayil J (November 2008). "Epigenetic biomarkers in psychiatric disorders". Br. J. Pharmacol. 155 (6): 7956. doi:10.1038/bjp.2008.254. PMID 18574461. Notes and references Adrian Bird (2007). "Perceptions of epigenetics". Nature 447 (7143): 396398. doi:10.1038/nature05913. PMID 17522671. PMID 17522671 Special report: 'What genes remember' by Philip Hunter Prospect Magazine May 2008 issue 146 Reik Wolf (2007-05-23). "Stability and flexibility of epigenetic gene regulation in mammalian development". Nature 447 (May (online)): 425432. doi:10.1038/nature05918. http://www.nature.com/nature/journal/v447/n7143/full/nature05918.html. Retrieved 2008-04-05. C.H. Waddington (1942) (1977). "The epigenotype". Endeavour 1: 1820. doi:10.1016/0160-9327(77)90005-9. According to the Oxford English Dictionary: The word is used by W. Harvey Exercitationes 1651 p. 148 and in the English Anatomical Exercitations 1653 p. 272. It is explained to mean partium super-exorientium additamentum the additament of parts budding one out of another. It is also worth quoting this adumbration of the definition given there (viz. "The formation of an organic germ as a new product"): t
Neuroscience: In their nurture
Can epigenetics underlie the enduring effects of a mother's love? Lizzie Buchen investigates the criticisms of a landmark study and the controversial field to which it gave birth.
Can epigenetics underlie the enduring effects of a mother's love? Lizzie Buchen investigates the criticisms of a landmark study and the controversial field to which it gave birth.
Epigenetic vs Syngenetic Permafrost i e Top Down vs Bottom Up Epigenetic permafrost forms as the average annual climate cools down Winters may be colder and last longer summers may be cooler or just shorter Most new permafrost is
http://www.crrel.usace.army.mil/permafrosttunnel/1g2b_Types_of_Permafrost.htm
Computational epigenetics - Wikipedia, the free encyclopedia
Various experimental techniques have been developed for genome-wide mapping of epigenetic information, ... Medical epigenetics: Searching for epigenetic mechanisms that play a ...
Various experimental techniques have been developed for genome-wide mapping of epigenetic information, ... Medical epigenetics: Searching for epigenetic mechanisms that play a ...
heory of epigenesis: the theory that the germ is brought into existence (by successive accretions) and not merely developed in the process of reproduction. ... The opposite theory was formerly known as the theory of evolution; to avoid the ambiguity of this name it is now spoken of chiefly as the theory of preformation sometimes as that of encasement or embotement.
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Russo V.E.A. Martienssen R.A. Riggs A.D. 1996 Epigenetic mechanisms of gene regulation. Cold Spring Harbor Laboratory Press Plainview NY.
Epigenetics
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I.B. Dodd M.A. Micheelsen K. Sneppen and G. Thon (2007). Theoretical Analysis of Epigenetic Cell Memory by Nucleosome Modification Cell 129:813-822.
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Morris KV (2008). "Epigenetic Regulation of Gene Expression". RNA and the Regulation of Gene Expression: A Hidden Layer of Complexity. Caister Academic Press. ISBN 978-1-904455-25-7. http://www.horizonpress.com/rnareg.
Mattick JS Amaral PP Dinger ME Mercer TR Mehler MF. RNA regulation of epigenetic processes. Bioessays. 2009 Jan;31(1):51-9. Review. PMID:
Does the impact of psychological trauma cross generations?
In groups with high rates of posttraumatic stress disorder (PTSD), such as the survivors of the Nazi Death Camps, the adjustment problems of their children, the so-called "Second Generation", have received attention by researchers. Studies suggested that some symptoms or personality traits associated with PTSD may be more common in the Second Generation than the general population. It has been ...
In groups with high rates of posttraumatic stress disorder (PTSD), such as the survivors of the Nazi Death Camps, the adjustment problems of their children, the so-called "Second Generation", have received attention by researchers. Studies suggested that some symptoms or personality traits associated with PTSD may be more common in the Second Generation than the general population. It has been ...
Colorful chaos today and tomorrow
http://www.colourlovers.com/blog/2009/06/28/eclectic-color-roundup-37
UNSW Embryology- Molecular Development - Epigenetics
Persistent epigenetic differences associated with prenatal exposure to famine in humans. ... We emphasize that epigenetic cancer treatments are currently a 'blunt ...
Persistent epigenetic differences associated with prenatal exposure to famine in humans. ... We emphasize that epigenetic cancer treatments are currently a 'blunt ...
19154003
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J. Shorter and S. Lindquist (2005). "Prions as adaptive conduits of memory and inheritance". Nature Reviews Genetics 6 (6): 435450. doi:10.1038/nrg1616. PMID 15931169.
Oyama Susan; Paul E. Griffiths Russell D. Gray (2001). Cycles of Contingency: Developmental Systems and Evolution. MIT Press. ISBN 0262650630.
Silvia Costa and Peter Shaw. 2006. 'Open Minded' cells: how cells can change fate. Trends in Cell Biology 17(3):101-106. doi:10.1016/j.tcb.2006.12.005
Online 'Mendelian Inheritance in Man' (OMIM) 105830
Jablonka Eva; Marion J. Lamb (2005). Evolution in Four Dimensions. MIT Press. ISBN 0-262-10107-6.
See also Denis Noble The Music of Life see esp pp93-8 and p48 where he cites Jablonka & Lamb and Massimo Pigliucci's review of Jablonka and Lamb in Nature 435 565-566 (2 June 2005)
a b O.J. Rando and K.J. Verstrepen (2007). "Timescales of Genetic and Epigenetic Inheritance". Cell 128 (4): 655668. doi:10.1016/j.cell.2007.01.023. PMID 17320504.
Cooney CA Dave AA and Wolff GL (2002). "Maternal Methyl Supplements in Mice Affect Epigenetic Variation and DNA Methylation of Offspring". Journal of Nutrition 132 (8 Suppl): 2393S2400S. PMID 12163699. available online
Waterland RA and Jirtle RL (August 2003). "Transposable elements: Targets for early nutritional effects on epigenetic gene regulation". Molecular and Cellular Biology 23 (15): 52935300. doi:10.1128/MCB.23.15.5293-5300.2003. PMID 12861015. PMC 165709. http://mcb.asm.org/cgi/content/full/23/15/5293.
Jablonka Eva; Gal Raz (June 2009). "Transgenerational Epigenetic Inheritance: Prevalence Mechanisms and Implications for the Study of Heredity and Evolution". The Quarterly Review of Biology 84 (2): 131176. doi:10.1086/598822. http://www.journals.uchicago.edu/doi/abs/10.1086/598822.
A.J. Wood and A.J. Oakey (2006). "Genomic imprinting in mammals: Emerging themes and established theories". PLOS Genetics 2 (11): 16771685. doi:10.1371/journal.pgen.0020147. available online
J.H.M. Knoll R.D. Nicholls R.E. Magenis J.M. Graham Jr M. Lalande S.A. Latt (1989). "Angelman and Prader-Willi syndromes share a common chromosome deletion but differ in parental origin of the deletion". American Journal of Medical Genetics 32 (2): 285290. doi:10.1002/ajmg.1320320235. PMID 2564739.
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http://www.pbs.org/wgbh/nova/transcripts/3413genes.html
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Largest ever epigenetics project launched
( King's College London ) One of the most ambitious large-scale projects in Human Genetics has been launched today: Epitwin will capture the subtle epigenetic signatures that mark the differences between 5,000 twins on a scale and depth never before attempted, providing key therapeutic targets for the development of drug treatments. The project is a collaboration between TwinsUK, a leading twin ...
( King's College London ) One of the most ambitious large-scale projects in Human Genetics has been launched today: Epitwin will capture the subtle epigenetic signatures that mark the differences between 5,000 twins on a scale and depth never before attempted, providing key therapeutic targets for the development of drug treatments. The project is a collaboration between TwinsUK, a leading twin ...
on the road bifurcation points at which energies for change either dissipate and dissolve in a way that allows the old attractor to reassert itself or shift the system into a new form Figure 6 The egg will find its way but which way Note 119 Changes in organizations New initiatives often generate their negation and it is difficult to say whether the solution will
http://www.ebbemunk.dk/technostructure/technostructurep4.html
US-SINO EPIGENETIC ASSOCIATION
Epigenetic Responses to Environmental Change and their Evolutionary Implications This article was written by Professor Bryan Turner for a meeting ...
Epigenetic Responses to Environmental Change and their Evolutionary Implications This article was written by Professor Bryan Turner for a meeting ...
MID 9825947.
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a b Tost J (editor). (2008). Epigenetics. Caister Academic Press. ISBN 978-1-904455-23-3 . ISBN 1904455239. http://www.horizonpress.com/epi.
Genome Res. 2009. 19: 427-437/doi: 10.1101/gr.086231.108
External links
The Human Epigenome Project (HEP)
The Epigenome Network of Excellence (NoE)
The Epigenome Network of Excellence (NoE)- public international site
DNA Is Not Destiny - Discover Magazine cover story
BBC - Horizon - 2005 - The Ghost In Your Genes
Epigenetics article at Hopkins Medicine
Towards a global map of epigenetic variation
v d e
The development of phenotype
Key concepts
Genotype-phenotype distinction Norms of reaction Gene-environment interaction Heritability Quantitative genetics
Genetic architecture
Dominance relationship Epistasis Polygenic inheritance Pleiotropy Plasticity Canalisation Fitness landscape Transgressive phenotype
Non-genetic influences
Epigenetics Maternal effect Dual inheritance theory
Developmental architecture
Segmentation Modularity
Evolution of genetic systems
Evolvability Mutational robustness Evolution of sex
Influential figures
C. H. Waddington Richard Lewontin
Debates
Nature versus nurture
List of evolutionary biology topics
v d e
Molecular Biology
Computational biology Developmental biology Functional Biology
Overview
Dogma
History of molecular biology DNA Replication (DNA) Transcription (RNA) - Translation (protein)
Element
(Genetic Heredity)
Promoter (Pribnow box TATA box) Operon (gal operon lac operon trp operon) Intron Exon Terminator Enhancer Repressor (lac repressor trp repressor) Silencer Histone methylation
Linked Life
Cell Biology Biochemistry Computational Biology Genetics
Engineering
Concept
mitosis cell signalling Post-transcriptional modification and Post-translational modification Dry Lab/Wet lab
Technique
Cell culture model organisms (such as C57BL/6 mice) method (Nucleic acid Protein) Fluorescence Pigment & Radioactivity High-throughput Technique (-omics): DNA microarray Mass spectrometry Lab-on-a-chip Gene regulation Epigenetic genetic post-transcriptional post-translational regulation Glossary
Cell culture model organisms (such as C57BL/6 mice) method (Nucleic acid Protein) Fluorescence Pigment & Radioactivity High-throughput Technique (-omics): DNA microarray Mass spectrometry Lab-on-a-chip Gene regulation Epigenetic genetic post-transcriptional post-translational regulation Glossary
K-State university receives patent for stem cells in umbilical cord
Kansas State University has been a issued a patent for a plentiful and noncontroversial source of stem cells from a substance in the umbilical cord.
Kansas State University has been a issued a patent for a plentiful and noncontroversial source of stem cells from a substance in the umbilical cord.
http://www.hkedcity.net/iworld/plan/view.phtml?iworld_id=54¤t_page=&feature_id=1788&page=2
