A groundbreaking study has unraveled the extraordinary genetic diversity of India’s population, tracing it back 50,000 years and uncovering links to health and disease susceptibilities.
A comprehensive genetic study involving over 2,700 individuals from across India has mapped the country’s rich genetic diversity, widely regarded as one of the most intricate in the world. Conducted by a global team led by Dr. Priya Moorjani from UC Berkeley, the research has been published in the prestigious journal Cell.
The study is the most detailed genomic survey conducted in India and delves deep into an evolutionary history dating back 50,000 years. It encompasses key periods from the initial human migration out of Africa to more recent influences of cultural practices like endogamy.
Researchers identified three major ancestral groups contributing to the genetic makeup of modern Indians: South Asian hunter-gatherers, Neolithic Iranian-related farmers and herders, and Eurasian Steppe pastoralists. These ancestries began to intermingle millennia ago, with significant Iranian farmer influence emerging from 4th millennium BCE farmers and herders in Tajikistan, known as Sarazm. Notably, artifacts like shell bangles found in Sarazm have parallels in ancient sites in Pakistan and Gujarat, indicating early trade and cultural exchanges with Indus Valley civilizations.
Over recent centuries, a demographic transition toward endogamy—marriage within one’s community—has shaped India’s genetic landscape. This practice has resulted in high levels of homozygosity, where individuals inherit identical gene copies from both parents. On average, each study participant shared a fourth-degree relative within the dataset, showcasing an uncommon level of genetic closeness in such large-scale studies.
This genetic structure elevates the risk of inheriting rare genetic disorders. The team documented over 160,000 previously unknown genetic variants, many associated with congenital conditions, metabolic diseases, and neurological disorders like dementia. Some variants, such as one linked to BCHE deficiency, are prevalent in certain Indian communities but absent outside the country.
The study also highlighted that Indian populations carry a higher diversity of genetic traits from archaic humans like Neanderthals and Denisovans than any other modern group. Approximately 1–2% of Indian ancestry is derived from these ancient relatives, with Indians also retaining a broader spectrum of archaic variants.
Some inherited traits may have assisted ancient Indians in environmental adaptation. Immune-related genes from Denisovans and Neanderthals could influence how modern Indians manage infections, including COVID-19. A notable gene cluster on chromosome 3, derived from Neanderthals, has been linked to severe COVID-19 symptoms.
Researchers also identified “ancestry deserts” in the genome, areas void of Neanderthal or Denisovan DNA. One such region includes the FOXP2 gene, crucial for human language development.
This extensive genetic mapping poses significant implications for public health, emphasizing the need for India-focused medical genomics. Global medical research often uses genetic data predominantly from European or East Asian populations, missing critical variants unique to South Asians.
By better understanding India’s genetic history, there is potential to enhance disease diagnosis, customize treatments, and design inclusive public health strategies. However, the research acknowledges certain limitations, particularly the scarcity of ancient DNA from India and Central Asia, which complicates the precise origin tracing of some ancestries.
As more ancient genomic data becomes available, scientists aim to refine these insights. Nevertheless, the findings underscore the lasting influence of ancient migrations, social customs, and archaic human interactions on the health of millions of Indians today.
Dr. Moorjani emphasizes, “Understanding our past is key to improving health outcomes in the future.”
According to NRI Pulse, the study opens new frontiers for addressing healthcare challenges by integrating India’s unique genetic heritage into global research paradigms.
Source: Original article