NS: Fossil DNA has clues to surviving rapid climate change

Well, actually one of six samples exhibited methylation, something which has been found once before. Proof of broad inheritance? No.

Fossil DNA has clues to surviving rapid climate change
by Bob Holmes

Surviving the last ice age was more than just a matter of growing a woolly coat. Rapid global temperature swings had to be matched by equally rapid adaptation. Now a remarkable find from Canada’s permafrost could help explain how the trick was done, through a process that might offer organisms a way to cope with the dramatic climate change the world is facing.

DNA extracted from the bones of an extinct bison shows that the environment influenced the way the animal’s genes worked without altering the genetic code. It is the best evidence yet that such epigenetic changes can be fossilised.

Inheritance doesn’t begin and end with genetic mutations. Environmental factors can modify DNA and lead to heritable changes in the way that genes are expressed – even though the genetic code itself is unchanged.

Brief encounter?

The big unanswered question is whether these epigenetic changes influence the long-term evolution and survival of a species, or whether they disappear too quickly to have any lasting impact.

Some evolutionary biologists favour the first option. They say that exposure to an environmental stress could trigger a useful epigenetic change in many members of a population simultaneously. The trait could then be passed down to most of the next generation.

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2 responses to “NS: Fossil DNA has clues to surviving rapid climate change

  1. Epigenetics doesn’t alter DNA. It alters RNA, which is a temporary cellular response to stress or non-stress. The alteration is temporarily inheritable, and the factors involved could be anything: food shortage/abundance, water shortage/abundance, heat or cold, you name it. This isn’t even remotely scientific.

  2. “DNA extracted from the bones of an extinct bison shows that the environment influenced the way the animal’s genes worked without altering the genetic code. It is the best evidence yet that such epigenetic changes can be fossilised.”
    This interpretation is incorrect. The bones were preserved by freezing. They were NOT fossilized. Fossilization replaces organic material with minerals.
    Preservation without fossilization is extremely rare, occurring only through freezing (which ends with the first thaw) or by hermetically sealing the material (as in amber).

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