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WORLD ANTHROPOLOGICAL UNION

CONGRESS 2024​

Paper

A study of A Single Variant Allele (rs1426654) of the Pigmentation Related Gene SLC24A5 Among Representative Cohort of Bengalee Caste Population

presenters

    Arkopala Bose

    Nationality: India

    Residence: India

    University of Calcutta

    Presence:Online

Skin pigmentation is one of the most distinctive features of human phenotypic diversity controlled by underlying genetic variations. The A allele of a non-synonymous substitution viz. rs1426654 of SLC24A5 accounts for lighter skin in Europeans. Previous studies in different caste and tribal populations of India suggested this variant also contributes significantly to skin pigmentation variation among Indians. In this context, the objective was to assess the quantitative measurement of skin pigmentation and its association with rs1426654 in a cohort of Bengalee caste population. We have quantitatively assessed skin pigmentation in 82 individuals using a tristimulus colorimter (Konica Minolta CR-10) from photo-exposed and photo-unexposed skin area. Individual Typological Angle has been calculated using L*(lightness), a*(redness), b*(yellowness) parameters. Genomic DNA was isolated from their saliva samples and genotyped for rs1426654 by PCR-RFLP method. To understand the association of SNP with skin pigmentation linear regression, chi square and T-test was performed. Examination on genotyping revealed derived allele frequency of A as 0.73. Subsequent analysis discerned significant (p<0.01) association between rs1426654 and constitutive pigmentation. Furthermore, based on ITA value, the participants were categorized into three categories i.e., brown, tan, and intermediate. A significantly biased distribution (p<0.01) of A and G allele was found among these three groups with the least frequency of ancestral G allele in the intermediate group (comparatively fair). Analysis of the difference of ITA values between photo-unexposed and photo-exposed skin colour unravelled significant difference (p<0.05) between AA genotype and other (AG and GG) genotypes. The present study corroborates with the earlier studies among the Indian population reported wide presence of the derived-A allele and strong association of rs1426654 with constitutive skin pigmentation. It not only contributes to the constitutive pigmentation but also towards the tanning process, as understood from the difference of skin pigmentation scores between the photo-unexposed and photo-exposed areas.

Keywords:

SLC24A5, Derived allele, Individual Typological Angle, Tanning