Convergent adaptation of human lactase persistence in Africa and Europe.
A SNP in the gene encoding lactase (LCT) (C/T-13910) is associated with the ability to digest milk as adults (lactase persistence) in Europeans, but the genetic basis of lactase persistence in Africans was previously unknown. We conducted a genotype-phenotype association study in 470 Tanzanians, Kenyans and Sudanese and identified three SNPs (G/C-14010, T/G-13915 and C/G-13907) that are associated with lactase persistence and that have derived alleles that significantly enhance transcription from the LCT promoter in vitro. These SNPs originated on different haplotype backgrounds from the European C/T-13910 SNP and from each other. Genotyping across a 3-Mb region demonstrated haplotype homozygosity extending >2.0 Mb on chromosomes carrying C-14010, consistent with a selective sweep over the past approximately 7,000 years. These data provide a marked example of convergent evolution due to strong selective pressure resulting from shared cultural traits-animal domestication and adult milk consumption.
Tishkoff
Sarah A
SA
Department of Biology, University of Maryland, College Park, Maryland 20742, USA. Tishkoff@umd.edu
Reed
Floyd A
FA
Ranciaro
Alessia
A
Voight
Benjamin F
BF
Babbitt
Courtney C
CC
Silverman
Jesse S
JS
Powell
Kweli
K
Mortensen
Holly M
HM
Hirbo
Jibril B
JB
Osman
Maha
M
Ibrahim
Muntaser
M
Omar
Sabah A
SA
Lema
Godfrey
G
Nyambo
Thomas B
TB
Ghori
Jilur
J
Bumpstead
Suzannah
S
Pritchard
Jonathan K
JK
Wray
Gregory A
GA
Deloukas
Panos
P
D000220:Adaptation, Biological; D000328:Adult; D000349:Africa; D000818:Animals; D018938:Caco-2 Cells; D005060:Europe; D019143:Evolution, Molecular; D005787:Gene Frequency; D006239:Haplotypes; D006801:Humans; D043322:Lactase / Q000235:genetics*; D007785:Lactose / Q000097:blood / Q000378:metabolism*; D007789:Lactose Tolerance Test; D008892:Milk / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D012641:Selection, Genetic
D043322:Lactase; D007785:Lactose