was further strengthened after the fall of the Timurids and the rise of the Shaybanid Uzbek Khaqanate that finally shaped the Turkic language and identity of modern Uzbeks, while the unique grammatical and phonetical features of the Uzbek language as well as the modern Uzbek culture reflect the more ancient Iranian roots of the Uzbek people. Genetic origins The modern Uzbek population represents varying degrees of diversity derived from the high traffic invasion routes through Central Asia. Once populated by Iranian tribes and other Indo-European people, Central Asia experienced numerous invasions emanating out of Southern Siberia and Mongolia that would drastically affect the region. According to a recent study on various Central Asian populations, the Kyrgyz, and Kazakhs share more of their gene pool with various East Asian populations, compared to Uzbeks, which are relatively closer to West Asian or European populations. The study further suggests that both migration and linguistic assimilation helped to spread the Turkic languages in Eurasia. Zhabagin et al. 2017 note that Turkic tribes arrived in the 7th century AD and became the dominant population in the region. Shortly afterwards, in the 8th century AD, the Islamic expansion reached the region but had no significant demographic impact. In the 13th century AD, the Mongolian invasion of Central Asia brought most of the region under Mongolian influence, which had "enormous demographic success", but did not impact the cultural or linguistic landscape. Genetic studies analyzing the full genome of Uzbeks and other Central Asian populations found that on average, 60% of the Uzbek ancestry is derived from East Asian sources, with the remainder ancestry (40%) being made up by European and Middle Eastern components. History Ancient history In the southern part of Central Asia there was a Bactria–Margiana Archaeological Complex, which has recently been dated to c. 2250–1700 BC. That name is the modern archaeological designation for a Bronze Age civilization of Central Asia, previously dated to c. 2400–1900 BC by Sandro Salvatori. Iranian nomads arrived from the northern grasslands of what is now Uzbekistan sometime in the first millennium BC. These nomads, who spoke Iranian dialects, settled in Central Asia and began to build an extensive irrigation system along the rivers of the region. At this time, cities such as Bukhara and Samarkand began to appear as centers of government and culture. By the 5th century BC, the Bactrian, Khwarazm, Soghdian, and Tokharian states dominated the region.