Natural Selection in DNA Methylation

[Recusant]

Yeasts have maintained their DNA methylation despite the fact that they lost the usual mechanism for this many millennia ago. Apparently it has been conserved through a previously unknown evolutionary process.

"Scientists uncover new mode of evolution" | LiveScience

Evolution and natural selection take place at the level of DNA, as genes mutate and genetic traits either stick around or are lost over time. But now, scientists think evolution may take place on a whole other scale — passed down not through genes, but through molecules stuck to their surfaces.

These molecules, known as methyl groups, alter the structure of DNA and can turn genes on and off. The alterations are known as "epigenetic modifications," meaning they appear "above" or "on top of" the genome. Many organisms, including humans, have DNA dotted with methyl groups, but creatures like fruit flies and roundworms lost the required genes to do so over evolutionary time.

Another organism, the yeast Cryptococcus neoformans, also lost key genes for methylation sometime during the Cretaceous period, about 50 to 150 million years ago. But remarkably, in its current form, the fungus still has methyl groups on its genome. Now, scientists theorize that C. neoformans was able to hang on to epigenetic edits for tens of millions of years, thanks to a newfound mode of evolution, according to a study published Jan. 16 in the journal Cell.

The researchers behind the study didn't expect to uncover a well-kept secret of evolution, senior author Dr. Hiten Madhani, a professor of biochemistry and biophysics at the University of California, San Francisco, and principal investigator at the Chan Zuckerberg Biohub, told Live Science.

[Continues . . .]

[Tank]

Not surprised as methelation can be inherited and impacts an organisms phenotype.