Shafaqna India: A group of local scientists have discovered an extremely rare indigenous gene that is the cause of the unusual phenomenon of red hair in a few Indians, and have in the process uncovered 21 novel variants of the same gene across 91 distinct population sets across the country.
The study focused on the Melanocortin 1 Receptor (MC1R) gene, which is one of the fundamental proteins regulating skin and hair colour in mammals. In India, the red hair colour (RHC) phenotype is extremely rare, according to the study.
“We analysed MC1R and identified an ultra-rare pathogenic variant, christened c.872C>A, that is responsible for the RHC phenotype in an Indian child. Further, we screened the complete coding region of MC1R in a total of 11,021 individuals, representing 91 distinct Indian populations across India, and found a total of 9 novel and 12 ultra-rare variants,” the researchers said.
The study began after scientists learnt about a five-year old girl from a village in southern India who had red hair on the scalp, body and eyebrows, while retaining dark brown-black eyes. The gene variant responsible for RHC had been inherited by the girl. Incidentally, her sister had black hair.
“Although RHC is found in 1–2 percent of the world population, its frequency varies greatly among populations of different ethnicities. However, in India, the RHC phenotype is extremely rare,” the researchers observed in their study. “Additionally, India has a diverse range of complexion tones, from pale to wheatish, brown and dark brown, across various ethnic populations,” they added.
Their study has been published in the July issue of HGG Advances, a peer reviewed international journal brought out by the American Society for Human Genetics. Experts from Centre for Cellular and Molecular Biology, Hyderabad, Tata Institute for Genetics and Society, Bengaluru, Institute of Genomics and Integrative Biology, New Delhi, Academy of Scientific and Innovative Research, Ghaziabad, Anna University, Chennai, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Indian Institute of Science, Bengaluru, Manipal Academy of Higher Education, Manipal, Banaras Hindu University, Varanasi, National Institute of Mental Health and Neurosciences, Bengaluru and SRM Institute of Science and Technology, Kattankulathur, were involved in the research.
“Our study identifies and functionally validates ultra-rare MC1R variants as potential causes of RHC phenotype in Indians. The distribution of some of these variants differed significantly among Indian populations. One of them is significantly associated with lighter skin pigmentation in the Bodh population inhabited in Ladakh,” the researchers said.
The study also observed a diversity of skin pigmentation among Indians, ranging from light to dark skin complexion. Generally, Dravidian speakers from Southern India have a dark complexion. In contrast, Indo-European speakers from northern India, genetically close to Middle Easterners, Central Asians, and Europeans, have lighter skin pigmentation. Similarly, Tibeto-Burman speakers from Himalayan and north-eastern states of India also have lighter skin pigmentation than south Indian populations.
