Monday, April 20, 2009

Human evolution symposium

Bronya Keats described how population bottlenecks (or founding) associate particular groups and genetic diseases. Also discussed the rate at which alleles for recessive disorders are naturally reduced from a population, and contrasted the normal statistical distribution of genotypes (given allele abundances) with the displaced equilibriums that arise where there is a heterozygote advantage. In the case of sickle-cell anaemia in malaria-affected populations, the gene statistics demonstrate that we are still pressured today by natural selection.

Neil Risch shared data suggesting an over-reaction to racism. Contrary to claims that race is genetically insignificant, machine categorisation of individual genomes does cluster according to race. At the same time, the degree of genetic diversity within each cluster can be used to trace the ancestry (i.e., founder effects from the original dispersal out of Africa). He also discussed the difficulty of race-related genetic effects being confounded by social effects (e.g., a disease risk-factor among African-Americans may have no effect in Africa).

John Hopper argued that it would be more cost-effective for the government to provide genetic testing after early detection (when it may improve cancer treatment) rather than to subsidise using the test to prescreen healthy people (which disproportionately favours the wealthy, and still produces neglegible benefits because the rare individuals that test positive are still not prepared to take significant risk-reduction measures such as prophylactic excision). Looking at his use of flow charts (and my own first aid training), I wonder why we do not have epidemiologists produce a 'curriculum' (a standardised treatment flowchart) for doctors (and instead, we trust the doctors to keep their own expertise up-to-date, knowing that they are being distracted by advertisers)?

No comments:

Post a Comment