Bangalore, April 2: A group of scientists in Bangalore has found a key that could unravel one of the mysteries of life.

The scientists ? in association with those from the US ? have tracked down human genes that induce mental retardation and debilitating muscular conditions. The breakthrough could help in early detection of ailments and warn who will be susceptible to them.

As many as 43 new genes (all on the X chromosome, one of the two that determine sex) have been listed by researchers at the Institute of Bioinformatics, Bangalore, and the McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, in the US.

?This is the foundation for the big step forward in pre-natal diagnosis of congenital mental problems like the Down?s Syndrome as well as muscular dystrophy and skeletal deformation,? said Krishna Deshpande, the institute?s director.

Down?s Syndrome is a genetic condition which causes mild to moderate mental retardation and changes the facial profile. Muscular dystrophy weakens muscles and a stage will come when they slowly stop working.

?Perhaps, new tools could be devised to screen families with a history of such health problems. Our success could encourage others to analyse other chromosomes for genes that trigger other ailments,? Deshpande added.

Deshpande said the breakthrough had been published in Nature Genetics, a reputed journal that has stringent standards and screening procedures.

?When the human genome was sequenced, the scientific community had a very vague picture that prompted all scientists to study every chromosome and gene in detail. Though this (sequencing) was a very long-drawn and arduous task, different groups worked on it. Our team analysed the data in a meaningful way and that helped in the discovery of these genes.?

Twenty-six scientists worked for over a year-and-a-half to list the genes.

Shreeharsh, one of them, said that apart from its crucial role in determining gender, the X chromosome could well be termed a storehouse of disease-causing genes.

?Our discovery could throw new light on mental retardation linked with genes or even unravel some genes that were not identified so far,? he said.

The institute?s chief scientific adviser, Akilesh Pandey, said: ?This is the first critical analysis of an entire chromosome done by a group that was not involved in determining the chromosome?s sequence. We did not 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.?

The team?s comparative study of the human X chromosome and genetic data of chimpanzees, rats and mice helped in the discovery of the new genes, he said.

Pandey, also an assistant professor at Johns Hopkins University, said the discovery was ?the acid test that bioinformatics efforts in India can be internationally competitive?.

The Institute of Bioinformatics, a non-profit research organisation, has launched several collaborative research projects in human genetics and proteins from the time it was set up here in May 2002.