Mailing List Archive

Mailing List: techdiver

Message Display

>  Marc, you do not find is interesteing that malaria and cycle cell come from
the 
> same region? Get serious , what do you think all of this is, happenstance? 

I'm not sure of the biochemsitry, but the genes that code for 
sickel-cell anemia also confer an increased resistance to malaria.  To 
the best of my understanding, it is NOT the sickel-cell effect per se, 
but an indirect correlation.  When you go to areas of high malaria, you 
find relatively high incidence of sickel-cell anemia.  The reason is, the 
folks who are heterozygous for the sickel-cell gene (i.e., they got the 
sickel-cell gene from one parent, and the "normal" gene from the other 
parent) have the best of both worlds - they don't have sickel-cell anemia 
(it's a recessive gene, so only the homozygotes get the disease), but 
they have some resistance to malaria. This is why the frequency of the 
sickel-cell genne is kept high in these areas. This is one of the classic 
examples used in text books to illustrate how natural selection leads to 
shifts in gene frequencies in populations (= evolution).

Aloha,
Rich

Navigate by Author: [Previous] [Next] [Author Search Index]
Navigate by Subject: [Previous] [Next] [Subject Search Index]

[Send Reply] [Send Message with New Topic]

[Search Selection] [Mailing List Home] [Home]