PMC:5985360 / 1882-2836 JSONTXT

{"project":"2_test","denotations":[{"id":"29526279-11423617-2046610","span":{"begin":173,"end":174},"obj":"11423617"},{"id":"29526279-12364370-2046611","span":{"begin":176,"end":177},"obj":"12364370"},{"id":"29526279-6583683-2046612","span":{"begin":855,"end":856},"obj":"6583683"},{"id":"29526279-6584911-2046613","span":{"begin":858,"end":859},"obj":"6584911"},{"id":"29526279-3752087-2046614","span":{"begin":861,"end":862},"obj":"3752087"},{"id":"29526279-2898142-2046615","span":{"begin":864,"end":865},"obj":"2898142"},{"id":"29526279-1376298-2046616","span":{"begin":867,"end":868},"obj":"1376298"},{"id":"29526279-17688704-2046617","span":{"begin":870,"end":871},"obj":"17688704"},{"id":"29526279-23542314-2046618","span":{"begin":873,"end":874},"obj":"23542314"}],"text":"Several hereditary variants in the hemoglobin genes afford protection against malaria (MIM: 611162). Many such variants are thought to have evolved in the last 10,000 years.1, 2 In the beta globin gene HBB (MIM: 141900), the sickle (MIM: 603903) allele βS is under balancing selection because of heterozygote advantage, which results from protection against malaria caused by Plasmodium falciparum and recessive lethality. The chromosomal background of the βS allele has been classified on the basis of the presence or absence of a set of seven canonical restriction sites, 5′ ε HincII → Gγ1 HindIII → Aγ1 HindIII → ψβ HincII → 3′ ψβ HincII → β AvaII → 3′ β BamHI, yielding five haplotypes, Arabian/Indian, Benin, Cameroon, CAR, and Senegal, named after ethno-linguistic groups or geographic regions, as well as a sixth category for “atypical” haplotypes.3, 4, 5, 6, 7, 8, 9 These designations do not necessarily indicate where the haplotypes originated."}