How the human race was split into three after M9(Euroasian) haplogroup?

Question

90% of people on earth excluding Africa shares the same haplogroup M9(Eurasian clan) which was split at central asia where the different human races were originated. Does anybody have a theory of what happened there? Please just intelligent answers!

Answer 1

it may be due to the geography where they entered asia in the middle east. Basically there are three directions to go and it appears that at least one group went each direction - south, east and north.