(Xinhua)
Updated: 2008-04-26 16:27

NEW DELHI - A gene mapping exercise of "people of India" shows that Indians are more vulnerable to HIV- AIDS than other population groups across the world because a protective gene marker against HIV-1 is virtually absent in the country, according to the latest study released by Indian Science and Technology Ministry.

The study also shows that the risk increases as one moves from north to south India. It also says the Indian gene pool is quite varied and the term or description "Indian" is hardly homogenous. It includes several variations across population groups spread across the country's land mass.

On the vulnerability to HIV-AIDS, the study says, "there is a high-to-low gradient from north to south (India). These results are consistent with the observations by Majumder and Dey in 2001, and the antenatal clinical HIV prevalence survey (2005) that reports a high frequency of HIV in south Indian populations."

The study, which was carried out by more than 150 scientists and researchers, is the largest scientific endeavor since Green Revolution effort in 1970s, the mapping covered four main linguistic families of Indians -- Austro-Asiatic, Tibeto-Burman, Indo-European and Dravidian. It also encompassed the mostly endogamous (marrying within the larger social group) Indian population defined by distinct religious communities, hierarchical castes and subcastes, and isolated tribal groups.

The study, a part of the Indian Genome variation initiative, has generated information on over 4,000 genetic markers from more than 1,000 biomedically important and pharmacogenetically relevant genes in reference groups. It reveals a high degree of genetic differentiation among Indian ethnic groups and suggests that "pooling" of endogamous populations without regard to "ethno- linguistic factors" will result in false inferences.

"We note that the people of India are referred as 'Indian' in many population genetic studies. The implication of such usage is that the Indian population is genetically homogeneous, which, as the results of our study indicate, is evidently not true. However, we have also shown it is possible to identify large clusters of ethnic groups that have substantial genetic homogeneity," it says.

The mapping is expected to help in constructing "specific drug response/disease predisposition maps" to aid policy decision making for drug dosage interventions and disease risk management, especially for complex and infectious diseases.