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 470Correspondence should be addressed to S.A.T. (Tishkoff@umd.edu).. 9 These authors contributed equally to this work. AUTHOR CONTRIBUTIONS S.A.T. conceived and supervised the study. S.A.T., K.P., H.M.M., A.R., J.B.H., M.O., M.I., S.A.O., G.L. and T.B.N. were involved in DNA collection and phenotype testing. A.R. performed the resequencing and initial identification of association of candidate SNPs with the phenotype. S.A.T. and F.A.R. selected the SNPs to be genotyped and samples to test for gene expression. P.D., J.G. and S.B. performed the SNP design and genotyping. F.A.R. processed and phased the raw data and performed the genotype-phenotype association analyses, plots of haplotype homozygosity from unphased data, dominance estimates and pairwise plot of LD. B.F.V. performed, and J.K.P. co-supervised, the iHS test to detect positive selection and plots of haplotype homozygosity from phased data as well as rejection-sampling analyses to estimate age of alleles and selection parameters. H.M.M. constructed the haplotype networks. C.C.B., J.S.S. and G.A.W. built the expression constructs, carried out transcription assays and analyzed the results of expression assays. The paper was written primarily by S.A.T., with contributions from F.A.R., B.F.V., J.K.P., C.C.B., G.A.W. and P.D. The supplementary information was written by S.A.T. and F.A.R. with contributions from B.F.V., J.K.P., C.C.B., G.A.W. and P.D. COMPETING INTERESTS STATEMENTThe authors declare that they have no competing financial interests.Published online at http://www.nature.com/naturegenetics/ Reprints and permissions information is available online at Published online at http://npg.nature.com/reprintsandpermissions/ Note: Supplementary information is available on the Nature Genetics website. 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 ~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. Europe PMC Funders GroupIn most humans, the ability to digest lactose, the main carbohydrate present in milk, declines rapidly after weaning because of decreasing levels of the enzyme lactase-phlorizin hydrolase (LPH). LPH is predominantly expressed in the small intestine, wh...
Objectives Malaria infection is still known to be a worldwide public health problem, especially in tropical and sub-tropical African countries like Sudan. A pilot study conducted to describe the trend of P. falciparum drug resistance markers in 2017–2018 in comparison to CQ and AS/SP eras in Sudan. The Pfcrt, Pfmdr-1, Pfdhfr, and Pfdhps genes were investigated. Data deposited by the worldwide antimalarial resistance network was consulted, and the molecular markers previously reported from Sudan were analyzed. Results Drug molecular markers analysis was successfully done on 20 P. falciparum isolates. The Pfcrt K76 showed high frequency; 16 (80%). For the Pfmdr-1, 9 (45%) isolates were carrying the N86 allele, and 11 (55%) were 86Y allele. While the Y184F of the Pfmdr-1 showed a higher frequency of 184F compared to Y184; 16 (80%) and 4 (20%), respectively. In the Pfdhfr, 51I allele showed higher frequency compared to N51; 18 (90%) and 2 (10%), respectively. For S108N, 18 (90%) were 108 N and 2 (10%) were S108. In the Pfdhps, all isolates were carrying the mutant alleles; 437G and 540E. The frequency distribution of the Pfcrt, Pfmdr-1, Pfdhfr, Pfdhps was significantly different across the whole years in Sudan.
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