POSTER NO: 601

High polymorphism at the MC1R gene makes a major contribution to phenotypic diversity in Eurasian populations

¹Nadira Yu. Yuldasheva, ¹R. Spencer Wells, ²Ruslan M. Ruzibakiev, ³Ashur R. Dostiev, ³Zulkhumor Abdullaeva, ⁴Behrouz Nikbin, ⁵Ramasami Pitchappan, ¹Susan Tonks, ¹Julia G. Bodmer, ¹Walter F. Bodmer
¹Cancer and Immunogenetics Laboratory, ICRF, Henry Wellcome Building for Human Genetics, University of Oxford, Oxford, UK, ²Institute of Immunology , Academy of Sciences RUz, Tashkent, Uzbekistan, ³Tajik State Medical Institute, Dushanbe, Tajikistan, ⁴University of Medical Sciences, Tehran, Iran, ⁵Madurai Kamaraj University, Madurai, India

Melanocortin-1 receptor (MC1R), the receptor for alpha-melanocyte stimulating hormone, is polymorphic and plays an important role in producing two types of melanin, pheomelanin (red) and eumelanin (black), which are present in human skin and hair. In this study we examined the distribution of MC1R gene polymorphisms in several Eurasian populations. A total of 2591 subjects from 49 populations were included in the present investigation. The subjects were not selected for skin and hair colour and were collected randomly. 5 variants of the MC1R gene (Val60Leu, Val92Met, Arg151Cys, Arg160Trp and Arg163Gln) were tested using ARMS-PCR. Arg151Cys and Arg160Trp alleles, which are common in individuals with red hair and fair skin, were found at highest frequencies in British (AF=0.128 and 0.069, respectively) and Orkadian populations (AF=0.106 and 0.099, respectively), with a decreasing gradient in the populations of European Russia to Central Asia. Previously reported to be common in European populations with light fair skin and light brown hair, allele Val60Leu was identified with high frequency in some populations of the Middle East, Europe and Caucasus. Central Asian populations showed middle range frequencies. The Val92Met variant was found to have an allele frequency from 0.194 to 0.01 in the middle meridian of Eurasia, with a maximum in Central and South East Asian populations. Our data suggest an increasing gradient of Arg163Gln frequency from Europe (0.039) to South East Asia (0.66). As anticipated, our data showed low frequencies of all investigated variants in the populations of South India with dark skin and dark hair. These results indicate that polymorphisms of the MC1R contribute to determining skin and hair colour is one of the significant factor in the phenotypic diversity found in different Eurasian populations and are consistent with the widely held assumption that genes influencing phenotypic variation in human skin and hair pigmentation are probably subject to selection associated with latitude and sunlight.