Jumping genes provide unexpected diversity

Mobile DNA elements help shape human genomes

CHICAGO ─ Mobile pieces of DNA may have given humans a jump-start on evolution, a new study reveals.

“Jumping genes,” pieces of DNA that replicate and insert themselves into a host’s genome, have been actively shaping human and other primate evolution, researchers said February 14 at the annual meeting of the American Association for the Advancement of Science.

Mark Batzer, a computational biologist at LouisianaStateUniversity in Baton Rouge, wanted to find out how much these jumping genes – known to scientists as transposable elements – have affected humans. To find out, Batzer and his colleagues compared the genomes of two humans. One genome was the genetic instruction manual assembled by the Human Genome Project. The other belongs to J. Craig Venter, a geneticist and entrepreneur who helped pioneer large-scale gene sequencing projects, including a privately funded human genome project. 

Batzer found 706 places where transposable elements had stuffed extra DNA into Venter’s genome. At the same time, recombination between the mobile elements cut 140 chunks out of Venter’s genetic instruction manual.

The finding indicates that transposable elements are unexpectedly potent contributors to human genetic diversity, Batzer says.

“We’re finding more and more variability than we would have predicted,” he says.

Tina Hesman Saey is the senior staff writer and reports on molecular biology. She has a Ph.D. in molecular genetics from Washington University in St. Louis and a master’s degree in science journalism from Boston University.

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