Hair Genetics : A Study Of Dna Sequence Variations Essay

1593 Words Nov 25th, 2016 7 Pages
A study of DNA sequence variations in melanocortin-1-receptors or MC1R genes found many variants of amino acid found in people who were red-haired but rarely found in the non-red people. Researchers have identified 3 common amino-acid-polymorphisms associated commonly with red haired people viz., R160W, R151C, & D294H. The abbreviated names mean common amino acid types were found in positions 160 151, & 294 in proteins are arginine (R), cysteine (C), arginine & aspartic acid (D), while amino acids histidine (H) & tryptophan (W), were found in the redheads (Catherine A Guenther, 2016).
Many rare polymorphisms of amino acid are there in MC1R genes, some may be linked to red hair. Surveys of genetic variations in genomes of big cross-sections of Icelanders found MC1R as one gene having strong links to red hair. However, knowledge of genotypes of individuals at a MC1R locus is insufficient for predicting if they will have red hair. It was found only 74% individuals homozygous for amino-acid tryptophan at the 160 position get red hair, and 4% heterozygous for tryptophan get red hair. It was also found that 5-pairs of twins who were dizygotic with identical genotypes for MC1R, had red hair for one twin while the other did not.
Literature Review:
Variety in hair colors has made summarizing results of different detailed family studies difficult. Davenport & Davenport (1909) had reported many examples of 2 brown-hair parents with red-hair offspring’s which…

Related Documents