BITS of DNA that love to roam may play a major role in shaping new
species.
Some pieces of DNA can copy themselves and leap into new locations on
chromosomes, but in mammals, it was thought that most 鈥渏umping genes鈥� are so
ancient and mutated that they are no longer mobile.
Now Haig Kazazian and his colleagues at the University of Pennsylvania in
Philadelphia say the house mouse has 3000 active mobile elements. By comparing
mouse species, they found the number of 鈥渞etrotransposons鈥� has multiplied even
within the past century (Nature Genetics, vol 20, p 288). 鈥淭hey are
still going like gangbusters,鈥� says Kazazian. The jumping genes may have created
the genetic differences that led to new species of mice and many other
animals.
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