The western Iranians.

 The western Iranians.

Three major ancient western Iranian groups were the Persians, Medes and Parthians. Until now we didn't have ancient DNA samples that could be securely linked to this groups. Iron Age samples from south of Urmia could be related partly to Medes but given their genetic profile and dating such linking was remaining speculative.

Amjadi et al. 2025 published first historic western Iranian ancient DNA samples that were either Parthians, either eastern Medes. The location (Marsin Chai, Vestermin) of those samples was in the border of Medes and Parthian satrapies so there is some incertitude how they were identified in their lifetime. (See the map).

Liarsangbon samples could be related to Medes given their more western location. It's remarkable that some of them had also slightly more western genetic profile. J1-620(xP58)>FGC6069 was found in Liarsangbon. Without much doubt of local origin. Another undefined J2a was also uncovered from that site in Parthian empire period.

Genome wide Achaemenid period samples from Marsin Chai were grosso modo looking similar to Bronze Age samples from the same region (TepeHissar, Shahtepe) nevertheless they are not identical.

Looking closer on the PCA it's clear that they are slightly more "northern" shifted. And in some cases slightly "western" shifted. The slight western shift could be of local origin but could be also from Sintashta/Andronovo cultures in Central Asia that had substantial Anatolian Farmer related ancestry.

Despite this no R1a was found from those ancient Iranian remains, only J2b2a2. This can mean that R1a was low but also can be due to sampling issue. Given that many samples were relatives and had the same Y DNA.

Overall those ancient Parthians/Medes have quite high Zagros/Iran Neolithic ancestry with low EHG/ANE. Also they have some South Asian related Onge/Andaman island Hunter Gatherer ancestry.

They are different from Urmia basin Iron Age samples which are more western and who plot close to antique era samples from Armenia. This difference can be due to geography but can be also related to different ethnic background. Ancient Medes samples from core Media are needed to understand this difference.

Returning to the R1a issue it must be noted that the R1a appear both in Armenia and Georgia at Achaemenid period. Even more interesting samples from Meskhetia region in Georgia yielded surprising results. Out of seven Y DNA from Sassanian period Meskhetia here were 2 cases of R1a and 2 cases of Q2 which almost certainly was introduced there by western Iranians. Another J1-P58>Z1853 from Meskhetia was also of non local origin. All this show that western Iranians must have more diverse Y DNA pool and more sampling is needed to understand their diversity.