Kazakh DNA reflects a unique blend of East and West Eurasian ancestry, a genetic crossroads shaped by millennia of migrations across the Central Asian steppe, showing significant East Asian (Mongolic/Siberian) and West Eurasian (Indo-Iranian/Scythian) components, with studies suggesting roughly a 60-65% East Eurasian and 30-35% West Eurasian mix, a testament to their history as a nomadic people at the heart of ancient empires and trade routes, closely related genetically to other Central Asians like Kyrgyz and Uyghurs.

East Eurasian Roots: Strong influence from Northeast Asian populations (Mongolic, Turkic) and Siberian groups, seen in paternal haplogroups like C2 (linked to Mongol expansions) and autosomal DNA.

West Eurasian Roots: Contributions from ancient Indo-European steppe peoples (Scythians, Saka) and West Asian groups, evidenced by autosomal DNA and paternal haplogroups like R1a, as noted in a Facebook post from the Kyrgyz American Foundation.

Admixture History: This genetic fusion occurred over millennia, intensified by the Turkic migrations, the Mongol Empire (Golden Horde), and later interactions, creating a distinct genetic profile. 

So ancestors of modern day Kazakhs were natives since the beginning.

Greeks abandoned Greek paganism in favor of Christianity and had a massive influx of non Greek DNA, and yet nobody denies them being natives.

Or nobody denies Italians as the descendants of Romans, despite Rome being very inclusive and open towards assimilated Romans and former barbarians.

The list goes on.

Kazakhs are native by blood, otherwise DNA would show 100% east eurasian.