Epigenetic Alterations, Easier and more controlled than regular genetic alterations.

[Kylonicus]

Has anyone else here heard of Epigenetics?

 

Essentially, what has to do with instead of altering the code itself, it alters the chromatin, which in turn silences or less a gene go full blast.

 

When the chromatin curls up the gene becomes silenced, when it is loose, the gene becomes heavily active.

 

The great thing about Epigenetics is, although it is less permanent, it is heridetary, and controlled by your environment, and especially various types of nutrients.

 

I believe(I think I am not the only one who believes this, a few, VERY few obscure scientist may think this also) that chromatin may be in a transitional state when notch signaling, a cellular signaling system associated with maturation, is downregulated.

 

I believe this could be used as a form of genetic therapy.

 

Anyway, if you would like more information

 

http://www.sciencemag.org/feature/plus/sfg/resources/res_epigenetics.shtml

 

Or type "Epigenetics" on the web.

 

Whatcha think?

[Auburngirl05]

The March 31 issue of Nature had a big article about this, if you want me to e-mail you the pdf just let me know.

[Dak]

its also believed that the acetylisation and methylation of the histone 'tails' of the chromatin may play a part in gene promotion, inhibition or silensing.

[Blade]

is Epigenetic s proper science?

 

meaning: is it philosophy?

 

is there peer review or is it in peer review process?

 

interesting information.

http://www.youtube.com/user/GenoTypeDiet

Edited July 18, 2008 by Blade
extra info found

[foodchain]

is Epigenetic s proper science?

 

meaning: is it philosophy?

 

is there peer review or is it in peer review process?

 

interesting information.

http://www.youtube.com/user/GenoTypeDiet

 

Yes its proper science. What is the big deal about epigenetics is it represents a non strictly dna alone aspect to inheritance and so on. A epigenetic factor, such as histone modification, can have a direct impact on say phenotype. I think the big question beyond simply understanding more about the issue, would be did say dna mutation produce epigenetic factors. I mean to think for a second what if the emergence of true life such as with prokaryotes which also posses cellular memory, had such elements at play beyond just mutation?

 

I am greatly confused as to the extent of impact mutation alone has on evolution overall past the microbial realm, and even then I question things such as with endosymbiosis. I mean if epigenetic factors held sway on that for instance, it would be so important to understand such.

[Blade]

PZ Myers (biology) and Abigail Smith (viruses) discussing Epigenetic s July 10 2008

 

http://bloggingheads.tv/diavlogs/12740

[jimmydasaint]

This is a simple minded explanation (typical for me) but I regarded epigenetics as the study of the way that certain genes are switched on and off in response to environmental conditions, for example, starvation, in a way that is inherited by future generations. However, in any single organism, the chromatin must be packaged in a way that certain genes are 'on' or 'off' by mechanisms mentioned in the previous posts, so that epithelial cells (epi=outside; thelial = layer) will always be replaced by other epithelial cells when damaged or killed.

 

IMHO, the organisation of chromatin is central to all differentiation anyway, which is the process in which cells containing identical genes become different - some becoming muscle and others becoming skin etc... however, in cases of starvation, it seems that the 'on' and 'off' pattern of genes is inherited by at least a generation after the original starving generation. This, I think gives the name to epigenetics.

[CharonY]

Well, generally epigenetics is usually a catch-all-phrase that includes any effects that effect gene expression, are are stable over a cell generation (but not necessarily a generation of the whole organisms) and finally, do not alter the gene sequence itself. A stable trait that is above the level of genes, so to say. Actually the oldest examples (a few decades old) include methylation of DNA, resulting in silencing of specific genes. The results can be very elaborate, like in the case if imprinting (which also require certain acetylation of histones).

 

Chromatin structures are more complicated, though. I have to admit that I am not an expert on this particular area (and there is a bloody large amount of studies in this area), however chromatin structure is heavily directed by a large number of proteins, both structural ones, as regulatory ones, and those in-between. I think in popular science it has become more prominent lately, as some believe that it challenges Darwinian evolution. Which is not really corrects as Darwin did not exclude Lamarckian modes of inheritance. The following neo-Darwinistic theories refuted Lamarck, though. Also the modern synthesis (to my knowledge) assumes that genes are the units of inheritance. However, the modern synthesis is undergoing so many changes in the last decades it only partially resembles its original form anymore.

But I digress.

To put it short, epigenetics is not a single mode of regulation, but encompasses a number of known and probably more unknown mechanisms of gene regulation. Epigenetic influence on chromatin structure is a bit newer (certainly newer than silencing by methylation), though it clearly still an interplay with a number of TFs and DNA binding elements. To my knowledge in tumour studies a link between Notch signaling and epigenetic silencing has been suggested a while ago, I have not followed that up, though.

However, I wonder what the OP means with "easier and more controlled"? More than what? The majority of fast responses will certainly be mediated by TFs, riboswitches and sRNAs, whereas epigenetic modification are certainly a major player in cell differentiation.

Edited July 19, 2008 by CharonY
could not spell. still can't

[foodchain]

Well, generally epigenetics is usually a catch-all-phrase that includes any effects that effect gene expression, are are stable over a cell generation (but not necessarily a generation of the whole organisms) and finally, do not alter the gene sequence itself. A stable trait that is above the level of genes, so to say. Actually the oldest examples (a few decades old) include methylation of DNA, resulting in silencing of specific genes. The results can be very elaborate, like in the case if imprinting (which also require certain acetylation of histones).

 

Chromatin structures are more complicated, though. I have to admit that I am not an expert on this particular area (and there is a bloody large amount of studies in this area), however chromatin structure is heavily directed by a large number of proteins, both structural ones, as regulatory ones, and those in-between. I think in popular science it has become more prominent lately, as some believe that it challenges Darwinian evolution. Which is not really corrects as Darwin did not exclude Lamarckian modes of inheritance. The following neo-Darwinistic theories refuted Lamarck, though. Also the modern synthesis (to my knowledge) assumes that genes are the units of inheritance. However, the modern synthesis is undergoing so many changes in the last decades it only partially resembles its original form anymore.

But I digress.

To put it short, epigenetics is not a single mode of regulation, but encompasses a number of known and probably more unknown mechanisms of gene regulation. Epigenetic influence on chromatin structure is a bit newer (certainly newer than silencing by methylation), though it clearly still an interplay with a number of TFs and DNA binding elements. To my knowledge in tumour studies a link between Notch signaling and epigenetic silencing has been suggested a while ago, I have not followed that up, though.

However, I wonder what the OP means with "easier and more controlled"? More than what? The majority of fast responses will certainly be mediated by TFs, riboswitches and sRNAs, whereas epigenetic modification are certainly a major player in cell differentiation.

 

 

 

I think Richard Dawkins is a flagship candidate for the gene centric view of biology. I think epigenetics or evo-devo is interesting because how does it equate into a gene centric view of life? Personally I don’t understand how gene centric view works, I understand importance of DNA, but its a part of a whole, DNA truly by itself is not even a virus.

 

Why epigenetics is important I think is that DNA is viewed in the central dogma as a one way street. With say modification of chromatin structure being posttranslational this includes the phenotype I think to a far greater extent in say population genetics for instance. I don’t think the central dogma is wrong by any means, I just do not think it includes all of the mechanisms that exist in that dogma, even if say its purely random dna mutations and mutations alone to describe say prokaryotes, this does not have to means is the only thing that counts as a molecular mechanism to describe the evolution of life.

[jimmydasaint]

I don't know about ESS but I assume it is too simplistic to assume that mutation, selection and reproduction in Natural Selection provides a complete description of an organism's interaction with its environment and the inheritance of subsequent traits. (I would also add in facilitated differentiation as a sub-note to phenotypic plasticity). I quote:

 

For sometime now there has been talk of a new Extended Evolutionary Synthesis (EES), and this article begins to outline why we may need such an extension, and how it may come about. As philosopher Karl Popper has noticed, the current evolutionary theory is a theory of genes, and we still lack a theory of forms. The field began, in fact, as a theory of forms in Darwin's days, and the major goal that an EES will aim for is a unification of our theories of genes and of forms. This may be achieved through an organic grafting of novel concepts onto the foundational structure of the MS, particularly evolvability, phenotypic plasticity, epigenetic inheritance, complexity theory, and the theory of evolution in highly dimensional adaptive landscapes.

 

http://lib.bioinfo.pl/pmid:17924956

[foodchain]

I don't know about ESS but I assume it is too simplistic to assume that mutation, selection and reproduction in Natural Selection provides a complete description of an organism's interaction with its environment and the inheritance of subsequent traits. (I would also add in facilitated differentiation as a sub-note to phenotypic plasticity). I quote:

 

I would say no. I think what is lost in looking at genes and selection is that if its selection that would define say fitness, then its adaptation right that wins or loses in time I guess. In this though if say epigenetic mechanisms are the product of genes as via selection this does not mean that epigenetic mechanisms cannot be different per say as with the fact that control of such can be considered cellular in some contexts I think, though don’t quote me on that.

 

So as life down on a gene level can act as like the most base units for natural selection to operate on if you want, some epigenetic mechanism possibly born from this process may influence evolution to a certain extent as another mechanism I guess is how I would say it. Such as both can express in the phenotype.

 

Personally if it were just a mechanism to act as some kind of an environmental logic gate for gene expression it still would have significance to evolution as it would rely to fitness heavily, but the fact that epigenetic changes can persist in reproduction while being able to effect the phenotype is a huge thing really, more so if such can be under cellular control. I think that such should be evident more so in norm of reaction, though I have not looked to much.

[CharonY]

I don't know about ESS but I assume it is too simplistic to assume that mutation, selection and reproduction in Natural Selection provides a complete description of an organism's interaction with its environment and the inheritance of subsequent traits. (I would also add in facilitated differentiation as a sub-note to phenotypic plasticity). I quote:

 

I am not sure I understand you. The modern synthesis has already included more aspects than mere natural selection as the sole driving force of evolution. The call for "newer" evolutionary theories arise at least partly from the fact that a number of the basic tenets of the modern synthesis have been found to be wrong or at least imprecise.

At the moment to my knowledge there are mostly publications pointing out these problems and calling for a new synthesis. These are sometimes called extended synthesis, as pointed out, though some other calls for something fancier, like postmodern synthesis. I have not followed this close enough to state whether a consensus will come soon or not.

[Mr Skeptic]

Why not anticipate a little and just call them Alpha Synthesis, Beta Synthesis, Gamma Synthesis, etc. That way, you don't need to know when modern is.