Study Reveals High Inbreeding Rate and Genetic Risks in South Indian Populations
New Delhi (The Uttam Hindu): A recent study analyzing the genes of South Indian populations has revealed a high inbreeding rate of nearly 60%. The historic practice of inbreeding, or endogamy, which involves marrying within small communities, increases the chances of passing down disease-causing gene variants, thereby raising the risk of genetic disorders.
Lead author Kumarasamy Thangaraj, a senior scientist at the Council of Scientific and Industrial Research (CSIR)-Centre for Cellular and Molecular Biology in Hyderabad, stated that endogamy is the primary cause of population-specific diseases in India. The study, published in the *Journal of Genetics and Genomics*, also reported a high prevalence of ankylosing spondylitis, a form of inflammatory arthritis, in the Reddy population of Andhra Pradesh.
The researchers attributed this finding to the presence of the 'HLA-B27:04' genetic variant, which increases the risk of ankylosing spondylitis, combined with a "strong founder effect." A founder effect occurs when a new population is formed by a small group of individuals, leading to a higher concentration of specific genetic traits. The practice of endogamy, deeply entrenched in the caste system, is significant in South Indian society.
Despite the prevalence of endogamous populations in India, comprehensive studies on the resulting disease risks have been limited, according to the research team. The study used the '1000 Genomes' dataset to analyze blood samples from 281 individuals from four populations: Yadav of Puducherry, Kalinga and Reddy of Andhra Pradesh, and Kallar of Tamil Nadu.
The analysis involved whole exome sequencing, a genetic test used to analyze individuals with a family history of diseases. The results revealed a high inbreeding rate of 59% across the populations studied.
Dr. Sarath Chandra Mouli Veeravalli, a rheumatologist at Krishna Institute of Medical Sciences, Hyderabad, noted, "We found a high incidence of ankylosing spondylitis in the Reddy community, who live in a specific geographical region of Andhra Pradesh."
The researchers also identified gene variants responsible for diseases and drug responses unique to these populations, with implications for personalized medicine. Thangaraj emphasized the need for "appropriate genetic screening, counselling, and clinical care for communities vulnerable to various health conditions."
The 1000 Genomes Project, which ran from 2008 to 2015, created a catalogue of common gene variations in about 1,000 individuals from Europe, Asia, and Africa, providing a valuable resource for genetic research.
