R1a-Z93: Exclusively Indo-Iranian Marker or Shared Turkic Legacy Too?

Hey everyone,

I've been digging deeper into R1a-Z93 lately, and honestly, the more I look at the maps and frequency data, the more I'm starting to question the standard narrative that calls it "the Indo-Iranian marker." Don't get me wrong, the association with Sintashta/Andronovo and the Aryan migrations into India and Iran makes a lot of sense on paper. You see sky-high frequencies among Pashtuns, many North Indians, Tajiks, Persians, etc. L657 branch exploding in South Asia especially fits the Indo-Aryan story nicely.

But then you zoom out to Central Asia and parts of the steppe, and things get... interesting. Look at the Turkic-speaking groups: Kyrgyz have solid chunks of Z93, Altayans too, and Bashkirs , wow, some samples show 70-80+% R1a, almost entirely Z93 (mostly Z2124 branch). Bashkirs are Volga Tatars' neighbors, speak a Turkic language, and yet they're basically swimming in this haplogroup. Compare that to actual Mongols or eastern Turks who have very little R1a overall mostly C, N, O, Q.

So how does that square with the idea that Z93 is purely Indo-Iranian? The classic explanation is heavy substrate admixture: early Turkic speakers roll in from the east (low R1a) and absorb local Iranic populations (Scythians, Saka, etc.) who already carried Z93 from Andronovo times. That works, sure. But is it the whole story?

What if the picture is more complicated? Some branches of Z93 look very Central Asian-native, and the highest diversity isn't neatly in the Pontic-Caspian steppe. Plus, ancient DNA from later periods (Iron Age, medieval Turkic) keeps showing continuity of Z93 in the same regions where Turkic languages later dominate. Makes you wonder: did Indo-Iranian speakers really "own" Z93 exclusively, or was it already widespread among various steppe groups that later got Turkified?

I'm not saying it's definitively "Turkic" in origin that would be a stretch but the automatic labeling as "Indo-Iranian only" feels increasingly simplistic. Curious what you guys think. Anyone have good sources or aDNA papers that clarify this?