Ghalichi et al. (2024) and the Indo-European Question

Ghalichi et al. (2024) and the Indo-European Question

A new paper by Ghalichi et al. (2024), which includes more than 100 ancient DNA samples, provides additional details about the interactions between Eastern European populations and West Asian populations across the Caucasus.

One particularly interesting result is a Mesolithic sample from the North Caucasus (Satanae Cave, SJG001), dated to around 6100 BCE. This individual shows a genetic profile almost identical to other Eastern European hunter-gatherers (EHG). The sample carried haplogroup R1a, although from a minor branch different from R1a-M417, the lineage later associated with many Indo-European expansions.

This finding suggests that the Yamnaya genetic profile did not exist from very ancient times, but instead formed after 6000 BCE. The Yamnaya population contains ancestry from both EHG and populations south of the Caucasus.

Formation of the Steppe Genetic Profile

The development of what is now known as the Steppe genetic profile appears to have been connected to the emergence of early farming cultures in the South Caucasus.

The Shulaveri–Aratashen–Shomutepe (SAS) culture began no later than 6200 BCE. From this period onward, farming populations mixed with Caucasus hunter-gatherers (CHG) and began to expand northward into the Caucasus steppe zone.

A new case of J2b2a-L283 has now been identified in the steppe zone of the North Caucasus (sample ZO1002, see map). This individual dates to 3800 BCE, making it older than both the Maykop and Kura–Araxes cultures. The sample already shows some EHG admixture, suggesting that it may represent a lineage descended from Shulaveri-related farmers who were attempting to settle in the steppe.

Later, this haplogroup would appear as a rare lineage within Yamnaya populations, before expanding significantly in the Balkans.

Predominance of Local Steppe Lineages

Despite these connections with populations south of the Caucasus, the most common Y-DNA lineages among Eneolithic steppe pastoralists remained those of local Eastern European origin, especially R1 and I2.

Additional examples include:

• a Nalchik farmer carrying R1b-V1636

• one of the oldest known R1b-M269 samples (KST001) from Konstantinovka, dated to around 3800 BCE

Two Key Questions

These findings raise two important questions:

1. Why do Eneolithic steppe groups and Yamnaya populations contain so few J haplogroups, despite their significant West Asian / Caucasus autosomal ancestry?

2. Which population spoke Proto-Indo-Anatolian—the Shulaveri farmers or the EHG-associated R1 populations?

Autosomal–Y-DNA Mismatch

Before addressing the first question, it is important to note that this mismatch between autosomal ancestry and Y-DNA lineages is not unique to Eastern Europe.

A similar pattern occurred in Western Europe. After the initial spread of G2 haplogroups with early Neolithic farmers, there was later a strong resurgence of the local I2 lineage. For example, in the British Isles, early farming populations sometimes show 100% I2 Y-DNA, even though their autosomal ancestry was about 70% derived from Anatolian farmers.

Possible Explanations

Several explanations have been proposed for this phenomenon.

One possibility involves social structure. Neolithic farming societies of West Asia may have had more egalitarian or even matrilineal social systems. A recent study of Çatalhöyük suggested evidence for matrilineal organization.

In contrast, Eastern European hunter-gatherer societies may have been more patriarchal. When societies with different social systems interact, this can affect uniparental markers differently: the Y-DNA of one group may dominate, while the mtDNA of the other group persists.

Another explanation sometimes proposed in popular discussions is mass killing of males during conflicts. However, this interpretation does not easily explain historical cases such as the Scythians, Saka, and Turkic tribes. These groups had strongly militarized cultures and often engaged in violent conflicts, yet they maintained very diverse Y-DNA lineages.

This suggests that warfare alone does not necessarily produce a single dominant haplogroup, since the outcomes of clan conflicts are often highly unpredictable.

When early farmers moved north of the Caucasus, they were likely the technologically more advanced population. It would be unlikely that they consistently lost every conflict without ever expanding their own lineages. Therefore, warfare and mass killing alone cannot explain the observed genetic patterns.

Other explanations may exist, but the social-structure hypothesis is one possible mechanism.

Linguistic Implications

The linguistic implications of these findings—particularly regarding the origins of Proto-Indo-Anatolian—will be discussed in a separate topic.