A team of scientists from India and the United States has uncovered new genes that are expected to speed research into diseases associated with the X chromosome and encourage similar analyses of other chromosomes.

By systematically comparing the human X chromosome to genetic information from chimpanzees, rats and mice, the scientists uncovered the new genes, many of which are located in regions of the chromosome already tied to disease.

"To our knowledge, this is the first time critical analysis of an entire chromosome has been done by a group that wasn't involved in determining the chromosome's genetic sequence," says study leader Akhilesh Pandey, an assistant professor at the McKusick-Nathans Institute of Genetic Medicine at Johns Hopkins University and chief scientific adviser to the Institute of Bioinformatics in Bangalore.

The analysis took place in Bangalore.

"We didn't start small. We wanted to prove that complete annotation can be done, and done in a way that lets you find new and unexpected things," Pandey said.

Regions of the X Chromosome, one of the two sex chromosomes, have been linked to mental disorder and numerous disorders, but finding the particular abnormalities involved has been difficult.

For 18 months, 26 Indian and US scientists pored through the publicly available sequence of the X chromosome to identify genes and other important parts of its DNA.