Western Asia, comprising the Arabian Peninsula, the Middle East, Anatolia and parts of the Caucasus, is genetically not obviously related to Central Asia. Briefly, western Asia was the entry point for the small human founder group emigrating from Africa just over fifty thousand years ago, and this group had not yet differentiated into Europeans, Asians or Australians. Today, however, western Asia is inhabited by people resembling, in their physical appearance as well as in their mtDNA and Y types, their European and Caucasian neighbours. To avoid ambiguity, people of European, Caucasian or western Asian descent will be termed “Caucasoid”, in contrast to the “Caucasians” of the Caucasus Mountains. In contrast, Central Asia has a different population history, and a different outcome. Because of the lack of ancient DNA evidence, nothing is known for certain on the initial settlement of Central Asia. We can perhaps extrapolate from ancient DNA recovered in Mongolia more than two thousand years ago, which turns out to be largely European, that Central Asia also must have had a largely European-derived or European-related population until two thousand years ago. This genetic constitution of the Central Asian population must then have changed via East Asian immigration, because Central Asia today has largely East Asian mtDNA and Y types. Thus, if there is any genetic link at all between western and Central Asia, it would be the sharing of a common Caucasoid substrate some time after fifty thousand years ago until becoming admixed more recently, with limited African female genetic input through historic slave trade in the Arabian Peninsula, and a de facto population replacement by East Asian DNA types in Central Asia in the last 2500 years. A small number of key studies have looked at the local history in detail, as follows.