Scientists uncover new mode of evolution
Scientists have discovered a form of natural selection that doesn't rely on DNA.
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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. /.../
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