title: Selective pressure has not acted against hypercoagulability alleles in high-altitude Amerindians.
abstract: Elevated hematocrit increases blood oxygen carrying capacity in high-altitude populations, but blood viscosity and coaguability may increase concomitantly. Alleles of the beta-fibrinogen gene (FGB) associated with lower fibrinogen levels are more common in highland Amerindians (Quechua) than lowland Amerindians (Na-Dene). Although genetic drift could account for this, selection may have acted against transmission of hypercoagulability alleles at high altitude. To test this hypothesis, we compared allele frequencies between Quechua and more closely related lowlanders (Maya) at loci in the genes encoding beta-fibrinogen (FGB), factors V (F5), VII (F7) and XIII (F13), alpha2-integrin (ITGA2) and plasminogen activator inhibitor type 1 (PAI-1; SERPINE1). No significant differences in allele frequencies were found except 485arg in the gene encoding factor V, which was more common in the Quechua. These data do not support the hypothesis that selection has acted to eliminate alleles associated with hypercoagulability in Andean highlanders.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, B.C., Canada. rupert@zoology.ubc.ca
authors.forename: J L
authors.initials: JL
authors.lastname: Rupert
authors.forename: M V
authors.initials: MV
authors.lastname: Monsalve
authors.forename: K K
authors.initials: KK
authors.lastname: Kidd
authors.forename: C
authors.initials: C
authors.lastname: Tan
authors.forename: P W
authors.initials: PW
authors.lastname: Hochachka
authors.forename: D V
authors.initials: DV
authors.lastname: Devine
mesh_terms: D000531:Altitude; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D007199:Indians, South American; D012641:Selection, Genetic; D019851:Thrombophilia / Q000235:genetics*