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Epigenome – the inheritance that is not in our genes – evolves faster than genome?

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Arabidopsis and the epigenome/Schmitz, Ecker

From “Are Genes Our Destiny? Scientists Discover ‘Hidden’ Code in DNA Evolves More Rapidly Than Genetic Code” (ScienceDaily, Sep. 16, 2011), we learn:

The study, published September 16 in the journal Science, provides the first evidence that an organism’s “epigenetic” code — an extra layer of biochemical instructions in DNA — can evolve more quickly than the genetic code and can strongly influence biological traits.

The subject, of course, is the boring little mustard weed Arabidopsis thaliana, whose sequenced genome helped to establish key facts about plants.

“Our study shows that it’s not all in the genes,” said Joseph Ecker, a professor in Salk’s Plant Molecular and Cellular Biology Laboratory, who led the research team. “We found that these plants have an epigenetic code that’s more flexible and influential than we imagined. There is clearly a component of heritability that we don’t fully understand. It’s possible that we humans have a similarly active epigenetic mechanism that controls our biological characteristics and gets passed down to our children. “

Even more surprising was the extent to which some of these changes turned genes on or off. A number of plant genes that underwent heritable changes in methylation also experienced substantial alterations in their expression — the process by which genes control cellular function through protein production.

This meant that not only was the epigenome of the plants morphing rapidly despite the absence of any strong environmental pressure, but that these changes could have a powerful influence on the plants’ form and function.

And have we now found a vehicle for evolution of new forms of life? Not so far. The study demonstrated only microevolution (small, usually reversible, changes). Arabidopsis remained Arabidopsis throughout the study.

What epigenetics really shows is that selfish gene calculations are nonsense.

See also:

New finds make some wonder what the human genome actually is … it sure isn’t what we used to think …

9/11: A chance to study epigenetics? The inheritance that is not “in our genes” exactly?

Epigenetic signatures: Another blow to the “it’s in yer genes” industry


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