There are two opposing views about origin of modern man. According 10 one view Homo erectus in Asia were the…
There are two opposing views about origin of modern man. According 10 one view Homo erectus in Asia were the ancestors of modern man. A study of variation of DNA however suggested African origin of modern man. What kind of observation on DNA variation could suggest this?
greater variation in Asia than in Africa
greater variation in Africa than in Asia
similar variation in Africa and Asia
variation only in Asia and no variation in Africa.
Solution
There are two models about origin of modern man (Homo sapiens sapiens)
(i) Multiregional model: According to this view, modern humans evolved in many parts of the world from regional descendants of Homo erectus who dispersed from Africa between 1 and 2 million years ago.
(ii) Monogenesis model: According to this view, African descendents of Homo erectus gave rise to modern humans.
In late 1980s, Rebecca Cann and other geneticists supported this view on the basis of DNA of living humans. They compared the mitochondrial DNA (mtDNA) of a multiathenic sample of more than 100 people representing four continents. The greater the difference between the mtDNAs of two peoples, the longer ago that mtDNAs diverged from a common source. By using bioinformarics, they concluded that the divergence of mtDNA of Africans from common source began just 200, 000 years ago, much to late to represent the dispersal of Homo erectus. Thus, there are greater variation in Asia than in Africa.