We learnt in a previous post (Evolution in Dashavtar) how modern Human-beings evolved from Primate ancestors. The currently accepted scientific belief is that this development took place in the African continent from where Homo-sapiens started spreading outwards. This Out of Africa migration theory states that beginning around 100,000-70,000 years BP (Before Present), Modern Humans started spreading to different parts of the globe replacing the earlier local hominids like Nenderthal Man and Homo erectus. The study of Genetic markers shows us that irrespective of Region/Religion/Color and Caste, Indians are the closest to Africans, more than ANY other population in the World! This genetic relatedness sugests that India was the FIRST stop for human beings coming out of Africa!! For me the significance lies in this understanding that modern Humans coming out of Africa, spread to the rest of the World via India!! Thus, it was from the sub-continent that waves of people migrated to other parts of Europe, Asia, Australia, and even the Americas. Indeed MODERN Human-being had reached India at least by 80,000 years BP; Europe by 40,000 years BP; and the Americas just about 14,500 years ago.
For those who have a background in Biology, I’m sharing a tidbit of technical information. Most Genetic studies involve tracing two types of DNA – the Y-chromosome or Y-DNA and the Mitochondrial or mtDNA. While, Y-DNA is passed solely from a father to his sons, the mtDNA is passed from a mother to all her offspring.
Scholars like Thangaraj et al.; Macauley et al have conducted series of studies on the Mt DNA of indigenous people of Malaysia and Andaman islands and these corroborate the notion that our African ancestors took a coastal route along the Indian Ocean around 65,000 BP to populate these regions. According to Forster and Matsumura‘s assessment of the genetic evidence, ENTIRE continents of Asia, Europe, and the Americas were colonized by descendants of this initial group which perhaps included as little as four-five hundred women!
According to a study conducted by Macauley et al in 2005, the entire landmass of Europe and Middle East was settled from an early offshoot of this migration that moved in once the Ice melted and climate in these regions improved. Another interesting study with a comprehensive analysis can be read here: {http://www.ncbi.nlm.nih.gov/pmc/articles/PMC379225/}. British Geneticist, Stephen Oppenheimer believes India to be the origin of all the Eurasian Eves and he claims that the ENTIRE populations of Central Asia, Middle East and Europe present today, have actually descended from four mtDNA lines that originated in the Indian sub-continent 50,000-100,000 years ago!!
Of course there were other populations coming out of Africa as well but presumably, we were the ONLY ones to survive and propagate throughout the WORLD. Another research regarding Haplogroup W also comes to the same conclusion as is evident from the Image below:
The reason for that is quite eloquently expressed by the famous sci-fi author Arthur C. Clarke in one of his bestsellers – In four great waves, with 200,000 years between their crests, the Ice Ages swept by, leaving their mark on the ENTIRE globe. Outside the tropics, cold glaciers slew those who had prematurely left their ancestral home; and everywhere they winnowed out the creatures who could not adapt. Presumably, WE were the only ones who survived this ‘winnowing’ and were left with the responsibility to POPULATE the World!
With this ancient DNA comes the ubiquitous DIVERSITY of our people.. Our scriptures record a plural society since time immemorial proving that we have always been a pot-pourri of different colors, cultures and appearances. However, such a situation also makes it really difficult to understand our Genetic relatedness. Hence, 6 major laboratories with the help of Government of India, formed the Indian Genome Variation Consortium in order to undertake this Himalayan endeavor. IGVC preliminary results have revealed, that though India is a conglomerate of diverse ethnic lineages, they can still be clustered into broader groups of genetic homogeneity.
There have been numerous OTHER studies conducted on the same lines as well and let me share with you some examples: Macrohaplogroup M, a cluster of Proto-Asian maternal lineages, represents more than 60% of Indian MtDNA. Now, observe the similarities for this Haplogroup found in different populations of the country:
U2a – Punjab and Karnataka (North and South-west)
Mankind first developed in Africa, therefore, the first modern humans had large number of pigment producing cells called Melanocytes and thus had darker skin. People living in the tropics, directly under the Sun, produce increased quantities of Melanin in their bodies to shield them from the harmful UV rays. Thus, their darker color is a PROTECTIVE mechanism of the body to prevent the incidence of Skin Cancer due to prolonged exposure to Sunlight!! Dark-skinned populations have greater protection against other health problems related to exposure to strong Solar Radiation, including the Degradation of Vitamins such as Riboflavins, Carotenoids, Folic Acid etc. Melanin in the Eyes is also protective and people with Gray, Blue and Green eyes are in fact at a HIGHER risk of developing sun-related Ocular problems.
Ultraviolet B radiation produces Vitamin D but can also destroy Folate that is essential for babies growing in the womb. Dark skin protects from folate destruction allowing normal reproduction and since the UV levels are high year round, there is still enough for the body to produce Vitamin D! The Natural Selection Hypothesis suggests that lighter skin color evolved to optimize Vitamin D production in extreme northern and southern latitudes. Gradually, as we started moving out of Africa, some groups migrated and settled into cooler climates of Asia and Europe, and the selectivity for Melanin production decreased and mutations appeared, making the skin tone lighter. North or South of 46 degrees latitude, the dark-skin could not produce enough Vitamin D while light-skin could hence it thrived!
The Genetic variations of Mc1rand SLC24A5 have been shown to be most common among pale-skinned populations. Similarly, tanning evolved so tht when UV – B radiation increases in early spring, the skin gradually darkens and keeps getting darker over the summer. During the winter, as UV radiation wanes, so does the tan allowing appropriate protection against folate destruction yet providing sufficient Vitamin D production.. S Over thousands of years, these traits became incorporated in our Genes and successive generations are now born with the same color and features as acquired by their parents. Another example of such adaptation is the smaller extremities observed in the Mountain-dwelling races. This adaptation is summed up in Allen’s Law of Genetics which states that the protruding parts of a warm-blooded animal’s body (such as the tail, ears, and limbs), are SHORTER in animals of same species from colder regions.
The takeaway from this entire discussion seems to me to be two-pronged – ONE, of course, is that all the different so called ‘races’ are extensions of the SAME Species and reflect nature’s way to mold us into different shapes just as a potter creates different works of art on his wheel. SECOND and more pertinent for this blog is that We, INDIANS are Genetically, the OLDESThumaninhabitants of this planet outside of Africa. All non-African populations have Descended from Us and not only culturally, even demographically India is the Cradle of Civilization for the Entire World!
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