BOB HIRSHON (host):
Horizontal gene transfer. I’m Bob Hirshon and this is Science Update.
Some kinds of DNA can jump from one species to another, and have probably done so throughout evolutionary history. This according to researchers at the University of Texas at Arlington. They found identical, self-replicating DNA segments called transposons in a South American parasitic insect and its pond snail host. Biologist Cedric Feschotte says they’ve found the same transposons in other species, including mammals. And that can’t be just a coincidence.
CEDRIC FESCHOTTE (University of Texas at Arlington):
The extreme level of sequence similarity, in the absence of any sort of selection that we can detect, is really strongly suggestive of transfer.
It’s not clear how the transfer happens. But since transposons make up nearly half the human genome, it’s possible that a good chunk of our DNA was somehow imported from other creatures. I’m Bob Hirshon for AAAS, the Science Society.