Specific population groups identified to check for mutations and prevent them from moving into next generation
HYDERABAD – Scientists at the Centre for Cellular and Molecular Biology (CCMB) and the Centre for DNA Fingerprinting & Diagnostics (CDFD) are screening specific population groups in identified areas ailing from peculiar genetic diseases to check for the mutations to prevent them from moving into the next generation.
Senior scientist and CDFD Director K. Thangaraj on Wednesday said that if the genetic mutation response is found in these groups during the ongoing study it will help in taking up counselling the populations concerned and halt the progression into the next generation. This is akin to what the Ashkenazi Jews have been successfully doing for the last few decades through community testing at the school level itself.
“When the adults consent to marry, their genetic sequences are compared and either they are advised against marriage or told to keep checking for the genetic disease when pregnant. The Jews have eliminated some diseases through this process, so hopefully, we too can do the same here,” he told an online gathering during the course of his presentation on ‘Human origin, health and disease’ organised by the National Geophysical Research Institute (NGRI).
Dr. Thangaraj stated that initially Ancestral South Indians (ASI) migrating straight from Africa and Ancestral North Indians (ANI) hailing from Europe through Africa, gave rise to many populations independently and during the last 2,000-4,000 years ‘admixing’ between these two founding populations of the country, gave rise to many diverse population groups.
This is evident from our varied skin colours across the sub-continent. However, this ‘admixture’ was halted 1,900 years ago due to endogamous marriages (within the group), and the caste system which came up later perpetuated this leading to the present populations, he explained.
“Genetically we are more homogenous, yet with every single population having a unique genetic affinity,” said the leading geneticist, pointing out that recessive genetic diseases increases in population in endogamous marriages with the abnormal chromosome having a chance to appear in the next generation.
The director said there is no archaeological evidence of when early humans migrated to the Indian sub-continent though it is thought to have happened 65,000 years ago through genetic evidence. Whereas there is evidence to show the migration happened to West Asia 47,000 years ago, Australia 50,000 years ago, China 39,000 years ago and Europe 40,000 years ago after modern man migrated from Africa 160,000 years ago due to a mega drought.
The country is found to have 4,655 well-defined population groups anthropologically, 533 tribes, 72 primitive tribes, 36 hunters and gatherers after analysing scores of samples. Tribal groups in Andaman & Nicober Islands have African features having migrated through South India and genome mutations of Great Andamanese, Onge and Jarawa (as there is no contact with the Sentinelese) on shown to be unique because they have been isolated for thousands of years, he added.
NGRI Director V.M. Tiwari also spoke in the programme held as a prelude to the India International Science Festival (IISF) at Goa on December 10-13 in hybrid mode, to the virtual participants.