they added on to the genepool established by the the Di-qiang populations that went before them.
Thus, Gansu is the major migration route East asians took to enter Xinjiang
1)Di-Qiang tribes went first, possibly by as much as a millenia before the Han dynasty, because the ZHou dynasty was established partly by Qiang people. Jiang taigong himself was a Qiang
https://en.wikipedia.org/wiki/Jiang_Ziya
2)then went the Han dyansty
3)then went the Tang dynasty
4)then went the modern mgiration wave by the Han chinese today
Thus, with thousands of years of East asian people populating Xinjiang, it's of no wonder that Uyghurs have significant East asian dna in them today.
Original Homeland of uyghurs, which is in today's western Mongolia:
Anatolian bastardized Turks aka 'pseudo-Caucasoid turks'(from Crusaders, Greeks, Persians, Hungarians, etc, etc):
Uyghur turk(though, his dark blonde hair hints of his Tocharian lineage)
Uyghur people's
https://en.wikipedia.org/wiki/Epicanthic_fold is the prime testimonial of their East asian heritage
Oldest Turkic relic in the world, and it's not in Xinjiang:
https://en.wikipedia.org/wiki/Orkhon_inscriptions
The
Orkhon inscriptions also known as
Orhon Inscriptions,
Orhun Inscriptions,
Khöshöö Tsaidam monuments (also spelled
Khoshoo Tsaidam,
Koshu-Tsaidam or
Höshöö caidam), or
Kul Tigin steles (
simplified Chinese: 阙特勤碑;
traditional Chinese: 闕特勤碑), are two memorial installations erected by the
Göktürks written in
Old Turkic alphabet in the early 8th century in the
Orkhon Valley in
Mongolia. They were erected in honor of two Turkic princes,
Kul Tigin and his brother
Bilge Khagan.
[1]
The inscriptions, in both Chinese and Old Turkic, relate the legendary origins of the Turks, the golden age of their history, their subjugation by the Chinese, and their liberation by
Ilterish Qaghan.
[2] In fact, according to one source, the inscriptions contain "rhythmic and parallelistic passages" that resemble that of epics.
[3]