Logic and evolution: DARC mutation and malaria lessens (Introduction)

by David Turell , Wednesday, September 23, 2020, 15:34 (1521 days ago) @ David Turell

From a population study in Africa:

https://www.newscientist.com/article/2254915-people-in-cape-verde-evolved-better-malari...

"People in Cape Verde evolved better malaria resistance in 550 years

"And one of the strongest examples of recent evolution in people has been found on the Cape Verde islands in the Atlantic, where a gene variant conferring a form of malaria resistance has become more common.

"Portuguese voyagers settled the uninhabited islands in 1462, bringing slaves from Africa with them. Most of the archipelago’s half a million inhabitants are descended from these peoples.

"Most people of West African origin have a variant in a gene called DARC that protects against malaria.

"One of the strongest examples of recent evolution in humans has been found on the Cape Verde islands in the Atlantic, where a gene variant conferring a form of malaria resistance has become more common. Around half the people on the outer islands have a variant in a gene called DARC that protects against malaria. On the more densely populated main island of Santiago, where there have been many malaria outbreaks over the centuries, about 80 per cent of people have the variant. Here, the protective variant is more common than other variants of West African origin, showing there has been strong selection for it."

From Wikipedia:

"Plasmodium vivax has a wide distribution in tropical countries, but is absent or rare in a large region in West and Central Africa, as recently confirmed by PCR species typing. This gap in distribution has been attributed to the lack of expression of the Duffy antigen receptor for chemokines (DARC) on the red cells of many sub-Saharan Africans. Duffy negative individuals are homozygous for a DARC allele, carrying a single nucleotide mutation (DARC 46 T → C), which impairs promoter activity by disrupting a binding site for the hGATA1 erythroid lineage transcription factor.[jargon]. In widely cited in vitro and in vivo studies, Miller et al. reported that the Duffy blood group is the receptor for P. vivax and that the absence of the Duffy blood group on red cells is the resistance factor to P. vivax in persons of African descent.[5] This has become a well-known example of innate resistance to an infectious agent because of the absence of a receptor for the agent on target cells."

Comment: An adaptation within our species.