A comprehensive comparison between the genomes of humans, rats, and chimpanzees have turned up dozens of new genes on the X chromosome (One of the sex chromosomes, the other is Y). The new genes sit in regions tied to X-linked mental retardation syndromes, which appear only in boys, and other disorders. The team includes scientists from India (Institute of Bioinformatics, Bangalore) and USA (Johns Hopkins), and the results appear in the April issue of the journal Nature Genetics.

X And Y chromosomes (Courtesy: Futura Sciences)For 18 months, 26 Indian scientists pored through the publicly available sequence of the X chromosome (information generated by the Wellcome Trust Sanger Institute in England and others) to identify genes and other important parts of its DNA. Of particular interest were regions of DNA which encode proteins: the scientists compared similar regions between mice, humans and chimps. They found 43 new gene-structures that encode proteins, some of which lie in regions that are already tied to genetic diseases such as mental retardation, among others. Almost half of the new genes don't look like any previously known genes, nor do they look like each other.
The benfit of such a comprehensive study would be enormous. Similar comparisons can be done for other chromosomes as well, thus giving scientists a new way of comparing similar diseases between different species. As a side benefit, this will also allow evolutionary biologists to compare protein encoding techniques between species and better decipher the evolutionary tree of life.