Joined: Sep. 2006
|Looking at the [malaria] statistics, I was quite surprised...But, here’s the whopper!!!|
Pop. #6 Nigeria: S-allele: I/U= 3.17; AA-homozyg: I/U= 3.23!!!!!
Yes, that’s right, the AA-homozygotes had a “slight” advantage, i.e., 3.23/3.17= 0.02 selective advantage.
You're calculating I/U, that is, the infected to non-infected ratio. So, yes AA has a "slight" advantage — for the malarial parasite. In fact, every single case indicated a higher percentage of infections for those without the sickle-cell allele.
Of course, just because there is a correlation, doesn't indicate whether the correlation is statistically significant. While PaV is still struggling with basic ratios (and rules for rounding), for those interested, the [malaria] study used an example from history to teach how we can use statistical analysis to determine if a correlation based on limited data is significant.
So, we have Haldane's suggestion in 1949. Then we have preliminary data first collected in 1965. Careful analysis indicates a significant correlation. What comes next? Class? ...blank stares... Class!? ...mumble, mumble... Right. Hypothesis and further testing. Perhaps, we should collect more data ...
Protective Effect of Sickle Cell Trait Against Malaria-Associated Mortality And Morbidity: This study allowed us to determine that sickle cell trait provides 60% protection against overall mortality and most of this protection occurs between 2-16 months of life before the on set of clinical immunity in areas with intense transmission of malaria.
... or determine if there is a correlation between the persistence of the S-allele and prevalence of malaria in migrating populations, or even attempt to find the posited mechanism.
|But, of course, you can do the calculation, and then tell everyone how sickle-cell anemia confirms Darwinism! |
Zachriel, angel that rules over memory, presides over the planet Jupiter.
Member AMF, Angelic Motive Force
Pushing planets on celestial spheres â€” one epoch at a time.