|Revelations about the mouse genome|
October 18, 2002
In the latest evidence that humans and mice are genetically similar creatures, scientists say that 99 percent of the genes in mice have human counterparts. Only about 150 mouse genes do not have similar versions in humans.
Francis S. Collins, of the National Human Genome Research Institute in Bethesda, Maryland, discussed the "revelations about the mouse genome" at the annual meeting of the American Society of Human Genetics in Baltimore this week. The research is to be published later this year.
While not unexpected, the findings confirm the notion that the mouse genome will help researchers pinpoint human genes and develop genetically modified mice for studying human health and disease. Collins presented work done by the Mouse Sequencing Consortium.
The findings are consistent with a comparative study of humans and mice published in May. Using their own draft of the mouse genome, scientists at Celera Genomics in Rockville, Maryland, found that only fourteen genes on mouse chromosome 16 are not present in humans.
All the othersmore than 700 mouse genesare found in humans, and most are grouped together and in the same order as in the mouse genome, the Celera researchers reported in Science.
Collins said the new study would revise downward the number of human genes, putting the total at fewer than 30,000. "If anything, the gene count has stepped back a bit" from previous estimates, he said.
The mouse genome is about fourteen percent smaller than the human genome, according to Collins. The reason is a higher rate of deletions in mice compared to humans since both species diverged from a common mammalian ancestor.
The rates at which mutations have occurred during evolution vary substantially across the mouse genome, he said.
In an update on the human genome, Collins reported that 90 percent of the sequence from the publicly funded project is 'finished,' which means the sequence is properly ordered with relatively few gaps and errors. The project is moving rapidly to a finished sequence, and researchers have not lost interest after the publication of the draft genome in 2001.
Looking to the future, Collins said that the availability of additional vertebrate genomes would accelerate work on the human genome. About a half dozen vertebrate genomes are being sequenced or are nearing completion. These include the rat, the chimpanzee, the chicken, and the dog.
"Two vertebrate genomes are good, but more would be better," he said.
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