Epigenetic evolution?

Question

Is there evidence for this or is it theoretical? Can epigenetics lead to speciation in the absence of mutation? Thanks.

BTW: I am NOT a creationist and I do know what a mutation is and what epigenetics marks are.

Answer 1

Heh. I actually gathered most of your BTWs just by the way you framed your question. ( :

There has definitely been some evidence of epigentic changes which could be evolutionary in nature. While these cases haven't led to major speciation events, there seems to be no reason to believe that they couldn't; like a lot of evolution it's difficult to conclusively prove that one thing or another had definitely been a cause in the past.

One of the most obverved of such phenomenon is referred to as 'paramutation'. It occurs when one gene produces a product that not just modifies the activity of another gene, but actually changes the gene itself in a permanent way. It has been observed extensively in corn (the link below describes this at length).

There have also been observed many instances (even in humans) where epigenetic changes were inherited for several generations instead of re-imposed in each one. And though evidence is shaky on this, there is no biomolecular reason to believe that such a change could not be made permanent (or as permanent as the DNA itself, anyway). Certainly for diseases like Angelman Syndrome, missing DNA that was epigentically removed isn't going to magically come back (link 2). Less intrusive methylation and the like is still up in the air.

Unfortunately, speciation isn't exactly a clear line even for biologists. There are different standards used for 'what is a species', each of which has different implications. It is possible that epigentic changes can cause isolation of different communities of a species as one can cope with an environment and another cannot. Certainly enough deletions and modifications of the underlying DNA can cause speciation (though some might view this as just another 'kind' of mutation).

All and all, I would go so far as to say that because epigentic effects CAN have an effect on evolution, they MUST do so... for a system as large, complex, and long as evolution, it would seem statistically ridiculous for it to be otherwise. The only question would be just how large that effect is.

Large enough to cause speciation by itself? Given the vast number of species which have existed throughout time, again it's probably easy money to suggest that at least one speciation event was caused by just about anything. It certainly wouldn't surprise me. But I probably wouldn't put TOO much money on it, either.

That's my take anyway, for what it's worth.

Answer 2

"Epigenetic evolution" is what would have been called Lamarckian evolution.

So there is not a lot of evidence for it. However, I have heard (but cannot find) of a study where they taught planaria to solve a simple T-maze by sugar rewards. The offspring of those planaria (by sexual reproduction) solved the T-maze faster than other planaria whose "parents" had not been exposed to the maze.
There was no selection, so no "genetic evolution".

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Supplemental:
(not in response to anything in particular)

Another case of "epigenetic inheritance" has occurred to me last night:
If there is a decades-long famine, children who grow up during that time will be malnourished, and will therefore be smaller than normal, even on reaching adulthood. Women who grew up in that time will therefore have a smaller uterus than normal, and therefore (in general) will have smaller babies than they would otherwise have had.
*These* babies, due to starting out smaller, will be smaller as adults - even if there is no longer a famine! So *their* children will still be smaller than normal, and so on.

So in this case, the smallness is inherited *epigenetically*. However, in a continued state of plentiful food after the famine, the situation will return to the norm, as children will gradually get larger over successive generations.

Answer 3

that's barely the yankee cult church homes, the domicile schooled and the twisted thinkers that attempt to rebut evolution - and that's purely the christian church homes view!! The Pope, Catholic Church, Church of britain and mainstream church homes all settle for the super bang and evolution!! Lord Carey the former Archbishop of Canterbury placed it o.k. – “Creationism is the fruit of a fundamentalist physique of recommendations to scripture, ignoring scholarship and serious gaining knowledge of, and sophisticated distinctive understandings of reality”!! marvelous that christians and atheists can agree and chortle at the same time even no count if that's at your price!!