Ever wondered how we Indians survive such pollution, germs, dust and adulteration in food and water?
The secret lies, apparently, in our genes.
A research published in science journal Nature on August 1 shows how Indians have much higher levels of immunity compared with other world populations because we carry natural killer cells that can detect and terminate infections early. And guess how we got the infection-busters? It was in course of a historic — rather, pre-historic — journey that our earliest ancestors undertook, say scientists.
The study — jointly carried out by the ULCA David Geffen School of Medicine, University of California, Department of Medicine, All India Institute of Medical Sciences, New Delhi, and the National Marrow Donor Program (NMDP), Minneapolis — has found that Indians acquired the KIR (killer cell immunoglobulin-like receptors) genes as a result of natural selection to survive the environmental challenges during their pre-historic coastal migrations from Africa.
While the tumultuous travel across sea, swamps, forests, mountains and deserts left many dead, it also helped them pick up vital genetic tricks of survival. It is believed modern humans evolved somewhere in east Africa roughly 2,00,000 years ago and slowly migrated across the globe.
The first people in India, China, southeast Asia, Australia, Papua-New Guinea, Philippines, Japan and Indonesia were blacks of African origin. India has about 60 crore Indo-Negroid Africoid people.
“Research revealed immunity cells like macrophages, neutrophils and natural killer cells have an unexpected complexity and sophisticated capability in detecting and terminating infections at the early stage,” Rajalingam Raja, one of the researchers at ULCA, told HT from Los Angeles.
The people who migrated most extensively (natives of America, India and Australia) carried high levels of immunity genes, which were acquired to survive the environmental challenges during the extensive prehistoric migrations, he said.
The study covered 42 early ethnic groups including the Hans Chinese, Australian aborigines, Hispanic, Cook Island and African American, Afro-Caribbean populations.