A DNA ticket from India to Iran

Where did we come fromrdquo is a curious question that is pondered as much as the more fateful one ldquoWhere do we go from hererdquo While some seek answers to these questions in spirituality others turn to science In early March a research team led by a Mumbai native traced the origins of presentday Indians to Sarazm an ancient sitein TajikistanThe research spearheaded by UC Berkeleyrsquos Priya Moorjani is said to be among the largest in its scope in terms of the number of DNA samples analysed ldquoOur genome holds the story of our ancestorsmdashit carries information about our parents grandparents and even ancestors from a long time agordquo Moorjani tells midday from California where she is now basedThe assistant professor at the Department of Molecular and Cell Biology was born in Mumbai to two accountants After completing a BE in Computer Engineering Moorjani moved to the USA and did her Masterrsquos in Bioinformatics and Genomics at the George Washington University in DC and then a PhD at Harvard She went on to finish her postdoctoral training at Columbia University and started her own lab at Berkeley in 2018ldquoIn our studyrdquo she says ldquowe examined DNA from 2700 people from India including most geographic regions speakers of all major languages and tribal and caste groupsmdashproviding a comprehensive survey of genetic variation in the country We sequenced their whole genomes and then compared these sequences to people living in other parts of the world as well as ancient DNA samples including Neanderthals and DenisovansrdquoDr Moorjanirsquos research has also confirmed previous discoveries linking Indians to Iranian farmers of yore Representation picGetty ImagesThe Denisovans are an ancient Paleolithic species named after the Denisova cave in Russia based on the fossils and sediments found there and their genetic analysis Further research established that Neanderthals and Homo Sapiens also lived in this cave at different timesMoorjanirsquos study confirmed what we already know previous findings about how most Indians derive their ancestry from three groups related to ancient Iranian farmers Eurasian Steppe pastoralists and South Asian huntergatherers More importantly the research was able to trace the origins of our Iranian farmer ancestors all the way to Sarazm a place whose name literally means ldquowhere the land beginsrdquo Now a UNESCO World Heritage site it dates back to the fourth millennium BCE and is regarded as an important repository of information about the development of trade and cultural interchanges in Central AsiaDr Priya MoorjanildquoWe found a common source of Iranianrelated ancestry from the early Neolithic cultures of Sarazm into the ancestors of ancestral South Indians ancestral North Indians AustroAsiaticrelated and East Asianrelated groups in India What was very interesting to us was that archaeological studies have also documented trade connections between Sarazm and South Asia including connections with agriculture sites of Mehrgarh and the early Indus Valley Civilisationrdquo says MoorjaniMoorjani is also fascinated by a new discovery that a majority of Neanderthal ancestry is found in India as compared to other populations worldwide which only retain a subset of this variation today ldquoIndians also harbour the diversity found in most Denisovan ancestry This suggests that Neanderthals and Denisovans may have lived in Indiardquo she statesBased only on genome sequencing Moorjani and her team were also able to pinpoint that most of the genetic variation in Indians today stems from a single major migration out of Africa that occurred around 50000 years ago with minimal contribution from earlier waves of migration ldquoI find both the findings of Sarazm as the source of Iranianfarmer ancestry and the large diversity of archaic ancestry in India to be very exciting This shows how dynamic our past was and how people from different regions and groups like archaic and modern humans had contact and connections with each other And the footprints of these events are hidden in our genomesrdquo she saysSpeaking about the research methodology involved Moorjani tells us that some of the samples analysed in the study were from a larger set collected in 2021 by an Indian governmentsanctioned study The Longitudinal Aging Study in IndiamdashDiagnostic Assessment of Dementia LASIDAD was a populationbased prospective study of ageing and its effects on social health and economic wellbeing The rest were ancient DNA samples from previous studiesDid the research make her miss India we ask ldquoWell I grew up in Versova I love Indian street food and I do miss Aamchi Mumbairdquo she says as she signs off27kNo of Indians whose DNA was examined