Wednesday, April 8, 2009

Junk in DNA Trunk

A new evolutionary hypothesis could explain why some species are better able to quickly and drastically evolve than others. Scientists at Murdoch University have found that those lifeforms with the most transposable elements (or "junk") in their DNA are also the most likely to have evolved significantly in the past. They believe that these inactive genes are utilized in reproductive cells to potentially create new and adaptive traits for a particular species. This would explain parts of the fossil record that show sudden and drastic spurts of evolution instead of the slow process of selection for random mutations. By comparison, human beings have greatly evolved over time, and our genome contains about 46% TEs. The coelacanth, on the other hand, has relatively few TEs and hasn't evolved at all in 400 million years. If this research plays out, it could also explain the unevolved brains of people like Rush Limbaugh, whose genetic lineage is woefully lacking in TEs. More details here.

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