in Yellow River and Yangtze Basin areas. It resulted huge population expansion and differentiation.
Those stayed in the Yellow River area are early Hans. Those left their agricultural crib expanded into the nearby hunter-gatherer territory, either killed or expelled them, or hybrid with them. They formed today's Chinese minorities, such as Zang, Miao, Yi, as well as other peoples in the East Asia, such as Korean, Japanese, Vietnamese. The pacific islanders, except Papua New Guineans, are the decendants of people living along Taiwan Strait.
Current northern Han are the later hybrids of original Han and norther nomadic tribes. Southern Han are the hybrids original Han and southern minorities.