"We know how many genes are in the mammalian genome, but that does not tell us how they carry out their jobs," said senior author Tian Xu, Professor and Vice Chair of Genetics at Yale University School of Medicine and a Howard Hughes Medical Institute Investigator. "We have found a way to systematically inactivate genes in the mouse genome so we can understand the functions of these genes."

After sequencing the human and mouse genomes, many scientists have shifted their attention to determining the function of all of those genes. The strategy is to mutate each gene, to observe the consequences, and investigate the molecular mechanisms. In the past two decades, only a small percentage of the genes shared by mice and humans have been analyzed in detail.

Genetic elements, called transposons, move from place to place in the DNA and allow material to be inserted or relocated. Bacteria swap antibiotic-resistance genes with transposons. Scientists have tailored this natural gene shuffling technique to insert genes and to mutate genes in fruit flies and simple organisms to learn the function of individual genes.

Transposons have proved to be valuable genetic tools for many organisms, but not for vertebrates and mammals. General application in mouse genetics was limited as they travel at low frequencies to limited locations, and had little capacity to carry DNA fragments.It tookXu's team six years to develop an efficient tool for genetic manipulations in vertebrates and mammals.

Xu and his colleagues at Fudan University in Shanghai, China finally chose a transposon called piggyBac that was originally identified in the cabbage looper moth. They discovered that it was stable and
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Contact: Janet Rettig Emanuel
janet.emanuel@yale.edu
203-432-2157
Yale University
12-Aug-2005