Discovery may lead to a review of the theory of evolution

[Techne]

It has to with the role epigenetics play during biological evolution. The genetic code is responsible for transmitting biological information from one generation to another. Various biomolecular machines are responsible for the accurate replication of the genetic code. Some mutations (mutations are not random in any ontologically interesting sense) happen when the code is not replicated with 100% accuracy.

It is now well-known that the genetic code is not the only information that can be transmitted from one generation to the next. The epigenome can also be transmitted.

How you may ask? Part of the answer lies with the ability of epigenetically related enzymes and their ability to methylate and demethylate cytosine (one of the DNA bases). The methylation status of cytosine acts as a switch for genes. Hypermethylated regions act as suppressors of gene activity. Gene expression activity in turn can affect morphology, metabolism, growth, development and just about any other facet of an organism. Differences in epigenetics is probably one of the biggest factors playing a role in the differences we observe between twins (remember twins have the exact same genetic code). Anyway, here is the article:

Inherited Epigenetics Produced Record Fast Evolution:

ScienceDaily (Feb. 29, 2012) — The domestication of chickens has given rise to rapid and extensive changes in genome function. A research team at Linköping University in Sweden has established that the changes are heritable, although they do not affect the DNA structure.

A brown Polish frizzle chicken, one of many varieties of domesticated chickens. The domestication of chickens has given rise to rapid and extensive changes in genome function. (Credit: © msibley / Fotolia)​

Humans kept Red Junglefowl as livestock about 8000 years ago. Evolutionarily speaking, the sudden emergence of an enormous variety of domestic fowl of different colours, shapes and sizes has occurred in record time. The traditional Darwinian explanation is that over thousands of years, people have bred properties that have arisen through random, spontaneous mutations in the chickens' genes.
Linköping zoologists, with Daniel Nätt and Per Jensen at the forefront, demonstrate in their study that so-called epigenetic factors play a greater role than previously thought. The study was published in the journal BMC Genomics.
They studied how individual patterns of gene activity in the brain were different for modern laying chickens than the original form of the species, the red jungle fowl. Furthermore they discovered hundreds of genes in which the activity was markedly different.
Degrees of a kind of epigenetic modification, DNA methylation, were measured in several thousand genes. This is a chemical alteration of the DNA molecule that can affect gene expression, but unlike a mutation it does not appear in the DNA structure. The results show clear differences in hundreds of genes.
Researchers also examined whether the epigenetic differences were hereditary. The answer was yes; the chickens inherited both methylation and gene activity from their parentages. After eight generations of cross breeding the two types of chickens, the differences were still evident.
The results suggest that domestication has led to epigenetic changes. For more than 70 % of the genes, domesticated chickens retained a higher degree of methylation. Since methylation is a much faster process than random mutations, and may occur as a result of stress and other experiences, this may explain how variation within a species can increase so dramatically in just a short time.
Nätt and Jensen's research may lead to a review of the important foundations for the theory of evolution.

More later.

 

[Ghost29]

Sorry what? Epigenetics has been known for a long time amongst geneticists. While epigenetics presents an interesting new facet to the heritability of traits, it has little to no bearing at all on the current theory of evolution let alone resulting in a review. This is sensationalist drivel.

 

[Swa]

Don't bet on it. Some dogmatic "scientists" will never let go.

 

[Swa]

Question. Does epigenetics show a different ancestral line like genetics show a different ancestral line like ERVs show a different ancestral line like fossils show a different ancestral line?

 

[Lycanthrope]

[video=youtube;kp1bZEUgqVI]http://www.youtube.com/watch?v=kp1bZEUgqVI[/video]

A nice easy-to-understand explanation of epigenetics, for anyone who may be interested.

Don't bet on it. Some dogmatic "scientists" will never let go.

Excuse me?

 

[Techne]

Sorry what? Epigenetics has been known for a long time amongst geneticists. While epigenetics presents an interesting new facet to the heritability of traits, it has little to no bearing at all on the current theory of evolution let alone resulting in a review. This is sensationalist drivel.

The short answer is that some form of Lamarckism will have to be incorporated into the evolutionary theory, hence a review is needed. Currently, the significance epigentic inheritence to evolutionary processes is uncertain.

 

[Techne]

Question. Does epigenetics show a different ancestral line like genetics show a different ancestral line like ERVs show a different ancestral line like fossils show a different ancestral line?

I am not aware of any study linking epigenetic changes to ancestral lines. In fact, I don't think epigenetics can be used to trace ancestral lines.

 

[w1z4rd]

Sorry what? Epigenetics has been known for a long time amongst geneticists. While epigenetics presents an interesting new facet to the heritability of traits, it has little to no bearing at all on the current theory of evolution let alone resulting in a review. This is sensationalist drivel.

What he said. This is certainly sensationalized drivel. Kinda expected though

 

[w1z4rd]

Don't bet on it. Some dogmatic "scientists" will never let go.

Least educated statement in this thread.

 

[Techne]

What he said. This is certainly sensationalized drivel. Kinda expected though

Well this just adds absolutely nothing to the thread . Take your personal issues somewhere else thanks :erm:.

Least educated statement in this thread.

I don't see why? It is actually trivially true what he said. Scientists can be dogmatic.

 

[w1z4rd]

[video=youtube;kp1bZEUgqVI]http://www.youtube.com/watch?v=kp1bZEUgqVI[/video]

A nice easy-to-understand explanation of epigenetics, for anyone who may be interested.

Thank you. Very informative video.

 

[Geriatrix]

I'm just here for that funky ass chicken.

 

[Techne]

I'm just here for that funky ass chicken.

The things people do to chickens....

 

[Techne]

Another epigenetics-related discovery that is going to force us to rewrite the textbooks about evolution among other things.

RNA Modification Influences Thousands of Genes: Revolutionizes Understanding of Gene Expression

ScienceDaily (May 17, 2012) — Over the past decade, research in the field of epigenetics has revealed that chemically modified bases are abundant components of the human genome and has forced us to abandon the notion we've had since high school genetics that DNA consists of only four bases

Sorry, no chickens, but here is a microscope...

Over the past decade, research in the field of epigenetics has revealed that chemically modified bases are abundant components of the human genome and has forced us to abandon the notion we've had since high school genetics that DNA consists of only four bases. Now, researchers have made a discovery that once again forces us to rewrite our textbooks. This time, however, the findings pertain to RNA, which like DNA carries information about our genes and how they are expressed. The researchers have identified a novel base modification in RNA which they say will revolutionize our understanding of gene expression. (Credit: © Attila Németh / Fotolia)​

 

[Ghost29]

The short answer is that some form of Lamarckism will have to be incorporated into the evolutionary theory, hence a review is needed. Currently, the significance epigentic inheritence to evolutionary processes is uncertain.

No, this is not Lamarckism at all. Lamarckism predicts that the more you use a certain trait, the more it will be enhanced and vice versa for a trait you use less. The common stated example is that of the giraffe whose neck grows from generation to generation through each parent trying to stretch their neck further.

Epigenetics on the other hand can have completely different effects to their causes. First of all, for an epigenetic change to be heritable, it must be contained in the germ line. So say smoking causes a change a modification in germ line cells, Lamarckism would predict that this would make us better smokers or at the very least, influence a trait vaguely related to smoking. What
we see in real life though is that many of these changes, should they have any effect at all, will effect a completely unrelated trait.

Another epigenetics-related discovery that is going to force us to rewrite the textbooks about evolution among other things.

RNA Modification Influences Thousands of Genes: Revolutionizes Understanding of Gene Expression


Sorry, no chickens, but here is a microscope...

Over the past decade, research in the field of epigenetics has revealed that chemically modified bases are abundant components of the human genome and has forced us to abandon the notion we've had since high school genetics that DNA consists of only four bases. Now, researchers have made a discovery that once again forces us to rewrite our textbooks. This time, however, the findings pertain to RNA, which like DNA carries information about our genes and how they are expressed. The researchers have identified a novel base modification in RNA which they say will revolutionize our understanding of gene expression. (Credit: © Attila Németh / Fotolia)​

Dude, as a scientist in the field I feel like you are just being patronizing. We know about RNA modification. We know there are added layers of complexity. This is why you can share 50% of your genes with a fruit fly but not look anything like a fruit fly. All in all, the points you bringing up enhance our understanding of evolution, rather than resulting in anything revolutionary.

 

[w1z4rd]

Dude, as a scientist in the field I feel like you are just being patronizing. We know about RNA modification. We know there are added layers of complexity. This is why you can share 50% of your genes with a fruit fly but not look anything like a fruit fly. All in all, the points you bringing up enhance our understanding of evolution, rather than resulting in anything revolutionary.

Well done. Nicely said.

 

[Techne]

No, this is not Lamarckism at all. Lamarckism predicts that the more you use a certain trait, the more it will be enhanced and vice versa for a trait you use less. The common stated example is that of the giraffe whose neck grows from generation to generation through each parent trying to stretch their neck further.

Epigenetics on the other hand can have completely different effects to their causes. First of all, for an epigenetic change to be heritable, it must be contained in the germ line. So say smoking causes a change a modification in germ line cells, Lamarckism would predict that this would make us better smokers or at the very least, influence a trait vaguely related to smoking. What we see in real life though is that many of these changes, should they have any effect at all, will effect a completely unrelated trait.

To be fair, I did not say Lamarckism per se but some form of it. What this means is that the inheritance of acquired characteristics (epigenetic in this case) must somehow be incorporated into evolutionary theory. This is exactly what epigentics suggests. You acquire certain epigenetic changes during your lifetime which may affect gene expression and this can be transmitted to future generations without any change in your actual genetic make-up (as in ACGT). The exact nature of these changes and how they affect the physiology of future generations is of course still being researched.

Dude, as a scientist in the field I feel like you are just being patronizing. We know about RNA modification. We know there are added layers of complexity. This is why you can share 50% of your genes with a fruit fly but not look anything like a fruit fly. All in all, the points you bringing up enhance our understanding of evolution, rather than resulting in anything revolutionary.

I don't know why you think I am being patronizing. I agree with the scientists of the study, it will revolutionize the way we think of mRNA translation. mRNA translation is of course important to evolution and we know almost nothing about the mechanisms of mRNA methylation or how it affects gene expression, physiology, heritable characteristics etc. A whole new field of research (epitranscriptomics if you want) has basically been opened with this kind of research by actual scientists in the field of epigenetics.

 

[Swa]

One question, does the epigenome get carried over to the next generation?
Sperm is basically nothing more than an information carrier so it will basically not contain much of it. If it does it will mostly be maternally.

 

[Techne]

One question, does the epigenome get carried over to the next generation?
Sperm is basically nothing more than an information carrier so it will basically not contain much of it. If it does it will mostly be maternally.

Yes, but research is ongoing just exactly how it is done. To give an analogy, consider the following.

1) A book containing written text. The book represents the genome and the text inside the book is analogous to the ACGT/nucleotide sequences of a cell.
2) We know a lot about how all the information in the book is copied, all the machinery involved in repairing mistakes and making copies etc.
3) In the book there are certain spots which dictate which parts should be read more or less than others and this is analogous to how transcription works.

Epigenetics adds an extra layer of control of transcription. It is analogous to bookmarks of a book saying "read here" or "don't read here". You acquire these bookmarks as you proceed through life and some of these bookmarks get passed onto the next generation (we don't exactly know how much is carried over or how much it affects future generations, research is being conducted to figure out these issues).

Part of the problem is trying to understand how the bookmarks (epigenetic marks) are placed in the right spaces after the book is copied. Polycomb proteins, methyltrasnferases, bromodomain proteins etc. all play a role, we just don't know what exactly is going on.

 

[Geriatrix]

Don't bet on it. Some dogmatic "scientists" will never let go.