Indeed, George
...and there is more evidence for natural selection in malaria.
Malaria selective 'push' went further, and the very 'handle' on human red cells, the surface antigen called Duffy, somewhere has been lost over the centuries, to counteract parasite infestation:
...
At the red cell membrane, the Duffy antigen is the molecule used by the parasite P. vivax to enter the red cell. The high association of Duffy antigen null rell cells in some groups of people with sickle cell trait suggested that the Duffy antigen might provide some protection against malaria (Gelpi and King, 1976). Later investigations showed the Duffy antigen to be the receptor by which the merozoites of P. vivax enter red cells. People who lack the Duffy antigen (FY*O allele) are resistant to P. vivax (Hamblin and Di Rienzo, 2000). The Duffy null phenotype is most common in people whose ancestors derive from regions in Africa where vivax malaria is endemic.
http://sickle.bwh.harvard.edu/malaria_sickle.html
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.kennislink.nl%2Fupload%2F88764_962_1031149743529-afb2K.jpg&hash=68b0dc888b6abd6d11ab6e530601cbe8)
more from: http://www.oucom.ohiou.edu/tdi/Topics_International_Health/Malaria_2.htm