The blood is not that 100% pure for Hans after thousands years of mix-up with the ethnic minorities.
Although there is large overlap between Han people (most have common ancestors going back 4000-6000 years from intermarriage and their many decedents) Han ethnicity also absorbed many other ethnic groups historically, though with a much less percentage. Han ethnicity itself is the product of many tribes to begin with a few thousand years ago. Han absorbed the southern Hun entirely, some Manchus, Khitan (Eastern Slavic people calls China Khitai), minorities in Southern China, Tibetans, Xianbei, Mongols, Sephardic Jews, Persians, Arabs, Turkic peoples, etc. The Manchus that started the Qing dynasty wasn't entirely the original Jurchen people of the Jin dynasty, they previously mixed with Han and Koreans through intermarriage.
Han people refer to more or less the decedents original central plains people a few thousand years ago, who they before settling the central plains is still up to debate. Some Chinese scholars have argued that many people of Shandong are decedents of Dongyi peoples based on archaeological finds and correlations with local culture. Starting mainly from the Qin dynasty 2200 years ago the people of the central plains have been migrating South and various migration groups have varying mixtures with ethnic minorities in the South, some with no mixture at all. Hakka for example originated from central plains and Northern China. Many Han people in lower Yangtze region are decedents of migrants from the central plains during the 5 barbarians period.
Uyghurs themselves are a mixture of various groups.
Lu Shuming 陆树铭 ethnic Han from Qingdao, Shandong. Historically Shandong people liked big beards and drank a lot of alcohol.
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