Personalized medicine: genes vs ethnicity; Venter vs Watson
Seema Singh -
Wednesday, August 20, 2008 2:00 AM
Few biologists would put their genome on the sequencing block to advance the science they passionately pursue.
James Watson, Nobel prize winner for medicine and discoverer of the double helix, and J Craig Venter, scientist-turned-entrepreneur who, in 2000, raced the Human Genome Project to sequence the entire human genome, did just that -- got their genomes sequenced and placed in the public domain.
Inevitable surprises have sprung up since then. Late last year Watson was shown to have a significant amount of DNA which is considered to be of African origin, barely a few months after he made the controversial remark that the Africans, as a race, are less intelligent than the Westerners. He claimed genes leading to differences in human intelligence could be found within a decade.
Now, a new analysis of genomes of these two scientists in today's issue of Clinical Pharmacology & Therapeutics suggests that personalized medicine is indeed personal, and medical practitioners should rely on precise genetic information, rather than race or ethnicity data, for prescribing drugs.
The study, co-authored by Venter, shows that the two Caucasian males --Venter and Watson-- differ considerably in their response to popular drugs like antidepressants or tamoxifen (cancer drug). And that's because the two genomes differ in a set of genes (Cytochrome P-450), which are known for metabolizing more than 75% of drugs.
Venter is likely to be an extensive metabolizer, while Watson's alleles suggest decreased metabolism. In addition, the allele (an alternative form of a gene) found in Watson is rare in the Caucasian population (3%) but is more commonly found in East Asian populations (49%).
Venter and his colleagues say that instead of limiting pharmacological advances to a particular race or ethnicity, identification of genetic biomarkers would enable broad therapeutic application. Because of the dramatic reduction in the cost of genotying, medical practitioners no longer need to guess the genetic make up of an individual.
Such a personalized approach might be difficult in India for various reasons, including the cost, but the Indian Genome Variation Consortium thinks India could possibly move towards ‘customized' medicine based on genetic data from ‘linguistic' groups. A new study, reported in Mint in April, has shown this is possible.