Limited evidence for adaptive evolution and functional effect of allelic variation at rs702424 in the promoter of the TAS2R16 bitter taste receptor gene in Africa.
Bitter taste perception, mediated by receptors encoded by the TAS2R loci, has important roles in human health and nutrition. Prior studies have demonstrated that nonsynonymous variation at site 516 in the coding exon of TAS2R16, a bitter taste receptor gene on chromosome 7, has been subject to positive selection and is strongly correlated with differences in sensitivity to salicin, a bitter anti-inflammatory compound, in human populations. However, a recent study suggested that the derived G-allele at rs702424 in the TAS2R16 promoter has also been the target of recent selection and may have an additional effect on the levels of salicin bitter taste perception. Here, we examined alleles at rs702424 for signatures of selection using Extended Haplotype Homozygosity (EHH) and FST statistics in diverse populations from West Central, Central and East Africa. We also performed a genotype-phenotype analysis of salicin sensitivity in a subset of 135 individuals from East Africa. Based on our data, we did not find evidence for positive selection at rs702424 in African populations, suggesting that nucleotide position 516 is likely the site under selection at TAS2R16. Moreover, we did not detect a significant association between rs702424 alleles and salicin bitter taste recognition, implying that this site does not contribute to salicin phenotypic variance. Overall, this study of African diversity provides further information regarding the genetic architecture and evolutionary history of a biologically-relevant trait in humans.
Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA.
Michael C
MC
Campbell
Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA.
Alessia
A
Ranciaro
Department of Biology, University of Pennsylvania, Philadelphia, PA, USA.
Daniel
D
Zinshteyn
Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA.
Renata
R
Rawlings-Goss
Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA.
Jibril
J
Hirbo
Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA.
Simon
S
Thompson
1] Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA [2] Biology Department, Addis Ababa University, Addis Ababa, Ethiopia.
Dawit
D
Woldemeskel
UMR 208, IRD-MNHN, MuseedeL'Homme, Paris, France.
Alain
A
Froment
Kenya Medical Research Institute, Centre for Biotechnology Research and Development, Nairobi, Kenya.
Sabah A
SA
Omar
Ministry of Scientific Research and Innovation, Yaounde, Cameroon.
Jean-Marie
JM
Bodo
Department of Biochemistry, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.
Thomas
T
Nyambo
Biology Department, Addis Ababa University, Addis Ababa, Ethiopia.
Gurja
G
Belay
National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, MD, USA.
Dennis
D
Drayna
1] Monell Chemical Senses Center, Philadelphia, PA, USA [2] Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ, USA.
Paul A S
PA
Breslin
1] Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA [2] Department of Biology, University of Pennsylvania, Philadelphia, PA, USA.
Sarah A
SA
Tishkoff
D000351:Africa, Eastern; D000483:Alleles; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D001592:Benzyl Alcohols / Q000494:pharmacology; D019143:Evolution, Molecular; D056726:Genetic Association Studies; D005960:Glucosides / Q000494:pharmacology; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000378:metabolism; D055697:Taste Perception / Q000235:genetics*; D000098706:Taste Receptors, Type 2
D000893:Anti-Inflammatory Agents; D001592:Benzyl Alcohols; D005960:Glucosides; D043562:Receptors, G-Protein-Coupled; D000098706:Taste Receptors, Type 2; C005696:salicin