Indo-European languages used to be represented by several branches in West Asia. The most ancient Anatolian languages (Hittite, Luwian, and Palaic) became extinct by ancient times, and its descendants (e.g. Lycian and Lydian) soon thereafter. Greek and Phrygian were added from the Balkans, and so did Armenian, which, according to tradition was derived from the Phrygian.
Unrelated to all these languages, to the east, were the Iranian speakers, the major branches of which extant today in West Asia are Kurdish and Persian (Farsi).
The boundary between the western Indo-Europeans and the east ones changed several times in history. The apex of Iranian power came early when the Achaemenids subjugated the entirety of Asia Minor, but the Iranian expansion was halted in Europe during the Persian Wars of the 5th c. BC. In the next century a reversal of fortunes resulted in the conquest of the Persian Empire by the Greeks of Alexander. The Hellenistic kingdoms lasted for centuries thereafter, but eventually succumbed and new Greco-Persian kingdoms arose that led to the Parthian revival which clashed with the new western power, Rome. The limit between East and West survived with victories and defeats on either side well into medieval times as the eastern Romans fought the Sassanids, the successor dominant power in the Iranian world. Heraclius ended the centuries-old struggle when he defeated the Sassanids in Mesopotamia, but the whole affair became irrelevant as soon thereafter the new power of the Arabs destroyed the Sassanids and threatened the Roman Empire itself which managed to survive for a few more centuries, before eventually succumbing to the Crusaders and Turks, but both of these probably had a minor effect on the local population. Greeks and Armenians continued to exist in Anatolia until the 20th century, with only remnants of them remaining in Asia Minor today.
To study the relationship between the various West Asian Indo-European groups, I gathered an Iranian sample (from Behar et al.), an Iraqi Kurdish one (from Xing et al.), an Armenian one (from Behar et al.), as well as an Armenian one from the Dodecad Project. I have also included the Behar et al. Turkish sample, and a new Turkish sample from the Dodecad Project.
Below are the first two dimensions of the MDS plot.
It appears that Kurds are not particularly closely related to their linguistic cousins, the Iranians. Neither are they very close to Turks and Armenians; the latter appear very close in most of my analyses, with the main difference being a small Mongoloid component in the former, which is not visible here due to the lack of Mongoloid reference populations.
The distinctiveness of the Kurds is also evident in the ADMIXTURE analysis:
The high blue component distinguishes Kurds from both Iranians and Armenians/Turks. Iranians have slightly more of it, suggesting a somewhat closer relationship. The difference between the small Dodecad Turkish sample and the Behar et al. one is suggestive of heterogeneity within Turks, so it is important to be aware of this. Hopefully, if more West Asian individuals join the project, we will be able to discover patterns of regional variation between and within different ethnic groups.