Implications of the Admixture Process in Skin Color Molecular Assessment

CAIO CESAR SILVA DE CERQUEIRA; TÁBITA HÜNEMEIER; JORGE GOMEZ-VALDÉS; VIRGÍNIA RAMALLO; CARLA DAIANA VOLASKO-KRAUSE; ANA ANGÉLICA LEAL BARBOSA; PEDRO VARGAS-PINILLA; RODRIGO CICONET DORNELLES; DANAÊ LONGO; FRANCISCO ROTHHAMMER; GABRIEL BEDOYA; SAMUEL CANIZALES-QUINTEROS; VICTOR ACUÑA- ALONZO; CARLA GALLO; GIOVANNI POLETTI; ROLANDO GONZÁLEZ-JOSÉ; FRANCISCO MAURO SALZANO; SÍDIA MARIA CALLEGARI-JACQUES; LAVÍNIA SCHULER-FACCINI; ANDRÉS RUIZ-LINARES; MARIA CÁTIRA BORTOLINI

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2014 vol. 9

1932-6203

The understanding of the complex genotype-phenotype architecture of human pigmentation has clear implications for theevolutionary history of humans, as well as for medical and forensic practices. Although dozens of genes have previouslybeen associated with human skin color, knowledge about this trait remains incomplete. In particular, studies focusing onpopulations outside the European-North American axis are rare, and, until now, admixed populations have seldom beenconsidered. The present study was designed to help fill this gap. Our objective was to evaluate possible associations of 18single nucleotide polymorphisms (SNPs), located within nine genes, and one pseudogene with the Melanin Index (MI) intwo admixed Brazilian populations (Gaucho, N = 352; Baiano, N = 148) with different histories of geographic and ethniccolonization. Of the total sample, four markers were found to be significantly associated with skin color, but only two(SLC24A5 rs1426654, and SLC45A2 rs16891982) were consistently associated with MI in both samples (Gaucho and Baiano).Therefore, only these 2 SNPs should be preliminarily considered to have forensic significance because they consistentlyshowed the association independently of the admixture level of the populations studied. We do not discard that the othertwo markers (HERC2 rs1129038 and TYR rs1126809) might be also relevant to admixed samples, but additional studies arenecessary to confirm the real importance of these markers for skin pigmentation. Finally, our study shows associations ofsome SNPs with MI in a modern Brazilian admixed sample, with possible applications in forensic genetics. Some classicalgenetic markers in Euro-North American populations are not associated with MI in our sample. Our results point out therelevance of considering population differences in selecting an appropriate set of SNPs as phenotype predictors in forensicpractice.