I think I'll stick with the academic papers, Bicicleur.
I'm aware that some bloggers refuse to acknowledge that anything related to Iran Neolithic or Iran Chalcolithic or Iran "anything" admixed into the EHG populations of the steppe, particularly at anything other than very minor percentages. Given other statements they've made in the past, I think some skepticism is warranted concerning their conclusions.
Usually, this admixture is labeled as CHG, which is based on genomes which are very ancient indeed, and I'm not aware of any evidence that a "pure" CHG population existed at the time of this admixture . Regardless, CHG is mostly Iran Neolithic, whether these bloggers like it or not, so I don't see the point of this refusal to acknowledge the ties with Iran. Also, the authors of this paper have proved to my satisfaction that the mixing agent was not Iran Neolithic "like", but Iran Chalcolithic "like" or perhaps various waves of migration of people whose impact is Iran Chalcolithic "like", which includes some Levant Neolithic.
the problem is that WHG, EEF, CHG and the like were defined when only a few anciant genomes were known
today more anciant genomes are known and better 'ancestral components' could be defined
and probably within 1 or 2 years more anciant genomes will be known that will qualify as even better 'ancestral components'
and yet, even if you would find the perfect 'ancestral components' after abt 4-8 ka everything becomes admixed with everything and things become so complicated that these models don't matter any more
IMO Iran Neolithic or Chalcolithic are allready hard to define because they are allready a complicated mixture themselves
there are some archeological arguments too to back up my theory, but the story becomes to long to tell
and I'm sure, in the best case I'll have to adapt that theory when more data become available, in the worst case it will prove wrong
for the moment, to me, taking everything into consideration what I know uptill now, it is the most parsimonious explanation
In the K=14 model of Genetiker I can see a CHG-like component in the Khvalynsk newcomer genome which is absent in the 2 other Khvalynsk genomes.
This Khvalynsk newcomer has mtDNA H, which is also new in Eastern Europe, except in Dnjepr-Donets.
So probably allready since ca 7.5 ka people were crossing the Caucasus into the Pontic Steppe and mixing with the local EHG.
But probably, later (5.7 ka) also Maykop would have brought more extra CHG or Iran Chalcolithic or something similar to the steppe. But that era already coincides with Yamna.
and let me remind you, after this study about the first farmers, I told there would be need for at least a 5th ancestral component with haplo G2a2 to explain the distribution of farming into Europe
soon after that was confirmed by the study with the Tepecik-Ceftlik and Boncuklu genomes