CHAPEL HILL A collaborative study by scientists at the University of North Carolina at Chapel Hill and The Jackson Laboratory in Bar Harbor, Maine, has found that the genetic variation in the most widely used strains of laboratory mice is vastly greater than previously thought.
Where previously there were only 140,000 variations in DNA sequence described, it turns out there are 8.3 million.
Moreover, the study found that the pedigrees of the 15 mouse strains studied are not what they were previously assumed to be. It appears they differ from each other to a far greater degree than do the pedigrees between humans and chimpanzees.
The research, published online July 29 in the journal Nature Genetics and slated for the September print issue, could have major implications for the interpretation and design of studies past and future.
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. We have rejected many long-held assumptions about the origin and relationships among mouse strains. In the light of our results, the conclusions of previous studies and the design of future studies need to be reevaluated, said study co-author Fernando Pardo-Manuel de Villena, Ph.D., associate professor of genetics at UNCs School of Medicine.
Animal models are essential tools in medical research because they allow researchers the opportunity to systematically probe questions within a defined biological system. The mouse is the most popular mammalian model for the study of human disease and normative biology, partly because their genomes are highly conserved. And, since 99 percent of genes in humans have counterparts in the mouse, cloning of a gene in one species often leads to cloning of the corresponding gene in the other.