HapMap the human haplotyping project has recently been released to the public domain. Haplotyping is a genetic method to determine the exact chromosomes a person has inherited from his parents. To go deeper in the details, a person usually receives two copies of the genome, on from his mother, the other from his father. That makes 23 chomosomes from each parent for a grand total of 46 chromosomes. These are usually redondant, however the mechanism is useful, as when a mutation appears on one chromosome (which usually means the chromosome becomes defective) then the “backup” copy can be expressed. This is rather simplified but the point is there. Now, if you do a genetic analysis on somebody, usually by gel-based electrophoresis, you’ll get the information contained on both copies but you won’t be able to tell which came from the father and which came from the mother. Nevertheless, geneticians being clever people, they turned to statisticians who devised ways to reconstruct haplotypes. This is all due to the fact that through thousands of years, the human genome tends to stay relatively stable (the mutation rate is estimated at about 10^-9 mutations per nucleotide per generation).

So, what’s the use of knowing which copy came from our mother and which from our father, you ask ? Well here is a quip from the HapMap homepage: “The goal of the International HapMap Project is to compare the genetic sequences of different individuals to identify chromosomal regions where genetic variants are shared. By making this information freely available, the Project will help biomedical researchers find genes involved in disease and responses to therapeutic drugs.” Particularly, by taking a sample of three different populations that have evolved somewhat idependently: caucasians, africans and asians, you can identify the regions that are different and that might explain why the individuals from these populations react differently. One prime example is the fact that most africans of the sub-saharan region are relatively immune to malaria. If we can identify the gene that is responsible for this immunity, we could perhaps create a better treatment or vaccine for this disease.

And there’s the rub. What if instead, a mad scientist were to decide to do some research on cloning. In particular, what would happen if he were to choose to create a “super” human who would have all the “good” characteristics found in the different populations while eliminating the “bad” ones. Well that might be a little far fetched (though some might recall certain hitlerian experiments). Rather, let’s look at something a bit more current. A cardiac disease preventing drug has recently been developped that has been found to be more effective in african-americans than in other sub-populations of americans. Now this drug is being prescribed to all african-americans while others are still treated with an older, and perhaps less effective, drug. Is that racism ? If, instead, the drug had been found to be more effective in caucasians, would that change your perception ? What if, instead it was a cure for AIDS aimed specifically at caucasians would it still be the same? It becomes clear that ethical problems are going to arise from this new research and answers will vary depending on wether future research benefits you or not.

Note: I raise these questions and answer elements but I am by no means in a position to give a “right” answer to them. Take with a grain of salt. You can find the full nature article here.

October 28th, 2005 | General Science