Changes in skin color are affected by mutations and the amount of UV light in the area where you live. Humans in Africa began to move around 120,000 BC and reached China around 100,000 BC. Full-scale migration begins around 70,000 BC and divides into three directions through the vicinity of Iran, where yellow races, whites, and Australians are born, and humans who did not leave Africa become blacks.

This has been clarified in a study of the Y-chromosome haplogroup. Since the Y chromosome is passed down from father to son, analysis of the Y chromosome can trace back to the paternal ancestors. As the alphabet progresses, it approaches the present age, and Q is said to have occurred near Iran around 17,000 BC Starting with the letter A, the Y-chromosome haplogroup A was born in Africa around 270,000 BC and is common among the Masai. to 22000 BC.

It travels from Africa to Iran in the figure below, and spreads from there to various places.
・ Asia, North and South America route, yellow race yellow line )
・ Middle East, Europe route, white race pink line )
・ Australia route , Australo-Melane blue line )
・ No movement, black race staying in Africa) Brown line )

1280px-Y-DNA_haplogroup_migration copy

Homo sapiens (modern humans), who evolved from Homo erectus, were all born in Africa around 200,000 to 100,000 BC, and left Africa around 70,000 BC and spread all over the world. The Denisovans and Neanderthals, also evolved from Homo erectus, were extinct around 20,000 BC. Until that time, Neanderthals, Denisovans, and Homo sapiens (humans) were crossed, and the gene was contaminated with modern humans.