The chicken has joined the growing group of animals whose genome has been sequenced. The findings, published today in the journal Nature, reveal that, like us, the bird has between 20,000 and 23,000 genes. But it has only 1 billion DNA base pairs to our 2.9 billion pairs. "The chicken has also been used extensively as a model by developmental biologists for over a century and the availability of a gene catalogue for the species will boost research in this area," says David Burt of the Roslin Institute in Edinburgh and a member of the International Chicken Genome Sequencing Consortium.

The results indicate that humans share about 60 percent of their genes with the chicken; humans and rats have 88 percent of their genes in common. The reduced number of base pairs in the fowl genome results in part from chickens possessing less so-called junk DNA than humans do. "The recognizable repetitive content of the chicken genome is only about 10 percent as compared to about 50 percent for humans," explains lead author LaDeana Hillier of Washington University School of Medicine. The team also found some unique common ground between people and chickens: for example, there is a chicken gene for interleukin 26, which is an important immune response in people and had not yet been identified in other animals.

The results should help scientists better understand basic developmental biology, as well as improve vaccine production models. "Genomes of the chicken and other species distant from ourselves have provided us with a powerful tool to resolve key biological processes that have been conserved over millennia," comments consortium leader Richard Wilson of Washington State University. "Along with the many similarities between the chicken and human genomes, we discovered some fascinating differences that are shedding new light on what distinguishes birds from mammals."

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