|LONDON- Scientists have cracked the genetic code of the chicken, showing it shares about 60 percent of its genes with humans and has a common ancestor that lived about 310 million years ago.|
With an estimated 20,000-23,000 genes, the draft sequence of the red jungle fowl, the predecessor of the domestic chicken, has roughly the same number of genes as humans.
It is the first bird and the first descendant of dinosaurs to have its genome sequenced.
Scientists hope to learn more about human developmental diseases such as cleft palate, muscular dystrophy, DNA changes linked to aging and genes involved in embryonic development by analysing the chicken genome.
The draft sequence may also help researchers breed more productive, disease-free birds which could limit the spread of viruses such as bird flu in Asia.
"The chicken is really in an evolutionary sweet spot," said Richard Wilson of Washington University School of Medicine in St Louis, Missouri, and director of the international consortium that mapped the genome.
"It's at just the right evolutionary distance from all the other genomes we already have to provide us with a great deal of fresh insight into the human genome," he added in a statement.
The consortium of more than 170 researchers from Europe, Asia and North America deciphered the genetic code of the red jungle fowl -- scientific name Gallus gallus -- in March. An analysis is published in the science journal Nature on Wednesday.
Although the estimated number of genes in chickens and humans are similar, the chicken genome is about a third of the size of the human genome. It contains about 1 billion base pairs, or chemical letters of the genetic code, compared to 2.8 billion in humans.
"Only 2.5 percent of the human genome has been conserved in both humans and chicken since their common ancestor a third of a billion years ago," Professor Chris Ponting, of the UK Medical Research Council Functional Genetics Unit in Oxford, England, said during a telephone news conference.
"We believe that the bits of the genome that are most resilient to change are those that have been most crucial to our survival throughout evolutionary history."
It is also where scientists will look for DNA mutations linked to human diseases.
Scientists have already identified a chicken gene for an important immune response protein that had only been found in humans.
Story by Patricia Reaney
REUTERS NEWS SERVICE