Friday, December 21, 2007

Breakthrough of the Year: Human Genetic Variation

Illustrating once again the important, fascinating and challenging issues raised by rapid advances in genetics, Science's editorial on the breakthrough of the year states:

The breakthrough of this year has to do with humans, genomes, and genetics. But it is not about THE human genome (as if there were only one!). Instead, it is about your particular genome, or mine, and what it can tell us about our backgrounds and the quality of our futures.

A number of studies in the past year have led to a new appreciation of human genetic diversity. As soon as genomes are looked at individually, important differences appear: Different single-nucleotide polymorphisms are scattered throughout, and singular combinations of particular genes forming haplotypes emerge. A flood of scans for these variations across the genome has pointed to genes involved in behavioral traits as well as to those that may foretell deferred disease liability. And more extensive structural variations, such as additions, deletions, repeat sequences, and stretches of "backwards" DNA, turn out to be more prevalent than had been recognized. These too are increasingly being associated with disease risks.

High-throughput sequencing techniques are bringing the cost of genomics down. The few "celebrity genomes" (e.g., Watson's and Venter's) will soon be followed by others, we hope in an order not determined by wealth but by scientific need or personal medical circumstance. Our natural interest in personal genealogy, accompanied by worries about our health, will create an incentive structure that even now is creating a sometimes dubious niche market for having one's genome "done."