Study: Lab mice more varied than thought

CHAPEL HILL, N.C., July 30 (UPI) -- U.S. researchers have discovered genetic variations in the most widely used strains of laboratory mice are vastly greater than had been thought.

Researchers at the University of North Carolina at Chapel Hill and The Jackson Laboratory in Bar Harbor, Maine, said previously only 140,000 variations in DNA sequence in such mice were described. The new study suggested there are 8.3 million such variations.

Moreover, the researchers discovered the pedigrees of the 15 mouse strains studied differ from each other to a far greater degree than do the pedigrees between humans and chimpanzees.

"Our article reports the first comprehensive analysis of such variation with an emphasis in evolutionary origin of the variation and its implications for biomedical research," said study co-author University of North Carolina Associate Professor Fernando Pardo-Manuel de Villena. "In the light of our results, the conclusions of previous studies and the design of future studies need to be re-evaluated."

The research is available in the online issue of the journal Nature Genetics and is to appear in the journal's September print edition.