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A new breed of genetically diverse laboratory mouse is close to being developed, according to a report in the online edition of the journal Nature.

It took scientists nearly a century to breed the first rats. In the early stage, the mice only carried some genetic diversity fragments of wild mice. Now there are hundreds and thousands of varieties of mice, but they have very few traits of human genetic characteristics, and there are great limitations in the study of genes causing human diseases. In order to change that, the U.S. department of energy's oak ridge national laboratory began a program in 2005 called collaborative hybridization to select new strains of genetically diverse laboratory mice.

The project has created a total of 30 inbred mouse families by selecting inbreeding and interbreeding with wild species. There are significant differences between the new mice and the ones currently in use: changes happened from coat color to the length of the tail, providing clues to the genes needed to fight infection.

In addition, the researchers tested about 66 inbred species for their susceptibility to aspergillus fumigatus, a soil fungus that causes respiratory disease in humans. The result was that the mice lived for four to 28 days after infection. Based on the genetic information of the new varieties and the sequencing of the genomes of the eight original varieties, the researchers mapped genomic regions containing a small number of genes during survival. The researchers are also using the same method to look for genes that appear in streptococcus pneumoniae.

At presents, the cooperative hybridization program, in partnership with the university of north Carolina, aims to produce several new mouse pairs by the end of this year and increase the breeding capacity to 100 by 2012.
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