A second possibility, that Indo-European languages came to Anatolia
along with small scale population movements and commerce, is also
described as consistent with the data. They note that "Among
comparative linguists, a Balkan route for the introduction of Anatolian
IE is generally considered more likely than a passage through the
Caucasus, due, for example, to greater Anatolian IE presence and
language diversity in the west."[11]
According to Wang et al. (2019), the typical steppe-ancestry, as an even
mix between EHG and CHG, may result from "an existing natural
genetic gradient running from EHG far to the north to CHG/Iran in the
south," or it may be explained as "the result of Iranian/CHG-related
ancestry reaching the steppe zone independently and prior to a stream
of AF [Anatolian Farmer] ancestry."[note 14] Wang et al. argue that
evidence for gene flow to the steppe allows for a possible Indo-
European homeland south of the Caucasus mountains. According to
this model, Indo-European languages could have been brought north
together with CHG ancestry, a scenario which could also explain the
early split of Anatolian. They note that "the spread of some or all of the
PIE branches would have been possible via the North Pontic/Caucasus
region and from there, along with pastoralist expansions, to the heart
of Europe."[91]
Lazaridis et al. (2022) state that the genetic evidence is consistent with
an origin of Proto-Indo-European either in the EHGs of the steppe, or in
the south (the southern arc), but argue that their evidence points to the
latter. They argue that genetic evidence from the 'Southern Arc', an
area which includes Anatolia, North Mesopotamia, Western Iran,
Armenia, Azerbaijan, and the Caucasus, allows the possibility of a West
Asian homeland for the Proto-Indo-European language.[note 15] In this
view, Proto-Indo-European emerged in the southern arc, and was
brought to Anatolia when Caucasus/Levantine-related ancestry flowed