CCMB: Caste system impacts skin colour

Hyderabad: Scientists of city-based Centre for Cellular and Molecular Biology, along with researchers from Estonia have sequenced whole genome related to skin colour and established genetic links to skin colour variations in the country.
Similar studies in the field of genomics on human health, like on heart diseases, may lead to developing personalised medicine in the future, said Dr Rakesh Mishra, director CCMB.

Said Dr Mishra, “Genetic studies on disease susceptibility and drug response on very large scales are needed to establish individual specific lifestyle advisory and medical prescriptions as it is clear that ‘one size does not suit all’.”

Researchers have found a new mutation variant of a gene that is responsible for skin colour in the Indian population in addition to other variants found in the European population. According to scientists, social structure defined by the caste system has a “profound influence on skin pigmentation”.

Researchers said the study reflected the influence of the strict marriage patterns and multi-layered endogamy, adding to the variation in skin colour contributing to the mosaic of skin tones.

The study, conducted by the scientists’ team led by Dr Kumarasamy Thangaraj at the CSIR-Centre for Cellular and Molecular Biology, Hyderabad, in collaboration with Estonian Biocentre, Estonia and five other institutes, was published on November 17 in the online edition of The Journal of Investigative Dermatology.

CCMB senior principal scientist Dr K. Thangaraj said, “The global spectrum of skin colour that we see across the world is contributed by several genes acting together. Change of skin colour from dark to white is an adaptation of our ancestors and is a reflection of the delicate balance between the skin being light enough at low ultra violet radiation zones to allow sufficient production of Vitamin D and dark enough at high UVR zones for photoprotection.”

He said India seemed to capture the centre stage in the arena in the diversity of skin colour. “We have populations with skin tones ranging from pinkish, fair, wheatish, brown to dark brown. It seems to be one of the perfect models to understand the genetic architecture of skin colour,” he said.

The research team analysed the entire gene and found another variant (rs2470102), which contributes to skin pigmentation variation in Indian subcontinent. Further analyses revealed that both variants (rs1426654 and rs2470102) together could better explain the variation in skin colour among Indian populations than considering each variant independently.