This Genome Is Fowl

Researchers have sequenced the genome of the red jungle fowl, an early version of what we know today as the chicken, giving scientists new insight into many human diseases and possibly avian flu.

The chicken serves as a model for human genetic diseases, including muscular dystrophy, epilepsy and immunological disorders. The sequence will also help farmers breed disease-resistant chickens, scientists say.

The International Chicken Sequencing Consortium published three papers in the journal Nature, detailing a plethora of chicken genome data, which contains 1 billion chemical letters -- one-third that of humans.

The chicken is also a model for human embryonic development, since the chicken egg is so readily available and easy to study. Having the animal's entire genome sequence will help researchers understand which genes are crucial during early growth.

"Much of what we know about human limb formation has been uncovered through studies of chickens," wrote Jeremy Schmutz and Jane Grimwood, Stanford researchers who wrote an analysis accompanying the three chicken genome papers.

Researchers can now compare the human and chicken genomes in order to identify important human genes, a field of study known as comparative genomics. Humans and birds shared a common ancestor about 310 million years ago, and any genes they still share are presumed by researchers to be important, otherwise evolution wouldn't have kept them around.

"The chicken genome is invaluable for shedding light on functional elements of the human genome and our unique evolutionary history," the authors wrote. "It also points the way forward to the great utility we can expect from the genome sequences of other carefully chosen species."

Researchers at Washington University in St. Louis performed the DNA sequencing, then sent out the data for analysis to researchers in England, Germany, the Netherlands and other locations around the world.

The results could help stem a potentially devastating avian flu pandemic, which could kill 100 million people and infect billions, according to World Health Organization estimates.

This year, the poultry version of avian flu, known as H5N1, has infected just 44 people (32 died) in Vietnam and Thailand. But if the flu mutates into a form that can jump from human to human, the outcome would be devastating. No vaccine yet exists for bird flu.

Scientists hope that having the entire chicken genome sequence available for research will speed screening of an avian flu vaccine.

"Having the genome sequence should help us to better understand the chicken's immune system," said Richard Wilson, a genome researcher at Washington University who led the international chicken project.

Until an outbreak in Hong Kong in 1997 killed six of 18 people infected with H5N1, researchers believed the virus could not jump from birds to humans. Since then, the virus has mutated, enabling it to infect other animals including cats and pigs. Scientists dread the jump to humans, which could cause a pandemic worse than the influenza pandemic of 1918.

While the genome sequence could offer new leads for avian flu research, epidemiology -- tracking the virus’ mutations and trying to predict what will come next –- will be more helpful, according to Henry Niman, president and founder of Recombinomics, a company that tracks the evolution of viruses.

"I think that the flu pretty much controls things and is not that dependent on chicken genome," he said.