Chinanews, Shanghai, February 15 – Han is the biggest ethnic group in China. However, according to Xie Xiaodong, an associate professor from the School of Life Sciences of Lanzhou University, pure Hans don't exist in China any more.Xie has recently finished his report on the DNA changes of ethic groups in southwest China. In his report he states that original Hans are generally believed to be those who lived in central China (including Henan, Shanxi, Jiangsu and Anhui), but Xie believes that the “Hans”were a political conception rather than a naturally formed ethnic group. For example, back in the Shang Dynasty (C. 1600 BC – C. 1100 BC), the Hans included all the residents of today's Xi'an, but they were considered as “aliens” in the late Warring States Period (475BC - 221BC). Even the legendary Yan and Huang emperors, the forefathers of today's Chinese, were not of the original Hans, as they were from today's Gansu and Shaanxi provinces.Due to mass ethnic migration caused by wars, exiles and military services, the original Hans have disappeared in ethnic integration, and their customs can only be observed among the Hakkas, who mostly live in parts of Guangdong, Fujian and Jiangxi provinces.