Ancient Kartvelians and the Formation of Iberia

The possible steppe connection and Indo-European affiliation of the Trialeti-Vanadzor culture has been known for a long time. However, its partial presence in the lands which in antiquity became known as Iberia and Caucasian Albania was a hindrance to accepting and promoting that theory. Today, ancient DNA allows us to better understand population shifts in the past and resolves these apparent contradictions.

The first Y-DNA chart is based on the data from the Skourtanioti 2024 paper. A single Y-DNA sample from western Georgia was not included in the chart.

The LBA-EIA (1500-800 BC) period is known in eastern Georgia as the Lchashen-Tsitelgori culture. The Y-DNA distribution from this period is very similar to that from Armenia, with a predominance of R1b and I2, which expanded during the Middle Bronze Age Trialeti-Vanadzor culture period. The two J2 samples are from the Bazaleti site, which was north of Mtskheta, close to the foothills of the Greater Caucasus range. One of them also had low steppe ancestry in autosomes, indicating the northern border of Trialeti-Vanadzor culture's impact. This corresponds to the geography of the region, dividing lowlands and highlands. (see the map)

A single G2a1 in the LBA suggests that the Kura-Araxes culture of central regions of Georgia could have a different Y-DNA structure than those from Kakhetia, who were predominantly J1.

In the Iron Age 2 (800-600 BC), the data size is small, with only one Y-DNA sample, which is G2a1.

The Early Antique period (600-300 BC) roughly corresponds to the formation of the Achaemenid Empire. R1a appears in both Georgia and Armenia, and we see a significant change in the Y-DNA distribution. G2a1 and an as-yet unknown branch of J2 (most likely a subclade of CTS900) are now the most important haplotypes. Unlike in Armenia, which during this period shifted south, in Georgia we can expect a different shift. Unfortunately, the qpAdm models from the paper do not have enough resolution to understand the possible direction of the shift. A familial grave from Bragdzor near the Shnogh village close to modern Armenian-Georgian border can provide a hint about the nature of the population that expanded in Iron Age east Georgia.

**The Bragdzor Family**

Three samples from Bragdzor were related to each other. The father and his brother had the same Y and mito DNA, J2 and K1a4c respectively. The Bragdzor father had very different autosomes compared to the contemporary Lchashenians. He is marked as an outlier in the AADR dataset. He had high CHG and virtually no steppe ancestry, similar to modern West Georgians, with no admixture from the Etiuni-Lchashen people. This indicates that he arrived in Bragdzor during his lifetime, around 800 BC. Incidentally, this date corresponds to the proposed age of separation of Georgian and Zan. Two languages usually separate when the geographic distance between them increases, typically as a result of migration.

Another indirect piece of evidence that the Bragdzor father and his brother were new migrants is the fact that his son's mother (most probably his wife buried in the same grave) was an Etiuni woman, suggesting that they did not have women from the same ethnic group when they arrived. In any case, the Bragdzor family did not leave a lasting genetic impact in northern Lori. Numerous samples from the same region in succeeding periods show no evidence of significant change.

On the other hand, the kinsmen of the Bragdzor father left an important impact in eastern Georgia, laying the foundation of Proto-Iberia, which became known as Iberia in the Hellenistic period. There are two other samples outside of Georgia with possible Kartvelian affiliation having similar autosomes to Bragdzor: one from Keti (G2a1, ~650BC) and another from Hellenistic-era Samsun. This latter was in most likelihood related to Zan people. All of them have high CHG, differentiating them from possible Caucasian Albanian sample who had Zagros Neolithic ancestry and lower CHG.

**Conclusion**

In conclusion, steppe migrants that arrived from north of the Caucasus 4500 years ago left an important impact in the South Caucasus that lasted until the Iron Age. In the Iron Age, multiple unrelated events resulted in significant changes. Near the Greater Caucasus range, mountainous people moved to the lowlands, and Iberia and Caucasian Albania formed. Meanwhile, in historic Armenia, Urartu's and the Orontid (Yervandunis) efforts to create centralized states resulted in a different change in the genetic profile. Most likely, the Achaemenid Empire also played a role in these genetic shifts in the South Caucasus, but the scant data do not permit to have definitive conclusions.

See also

• The possible homeland of Kartvelian languages

Remarks on Skourtanioti 2024 paper on the Genetic History of South Caucasus

This is the first paper with a large number of ancient DNA samples from Georgia. The bulk of them are from eastern Georgia, within the Kur-Araxian basin, which permitted the authors to compare the genetic histories of modern Armenia and Georgia. The time transect starts from the Early Bronze Age and the Kura-Araxes culture. Genome-wide, the Kura-Araxes samples from eastern Georgia are similar to those found in Armenia. The Y-DNA of all three samples is J1 (Z1842). We now have 12 Y-DNA samples from Kura-Araxes, and 9 of them (75%) are J1, which further reinforces the idea that J1-Z1842 expanded with the Kura-Araxes culture and was probably the most important Y-DNA in the northeastern parts of the Kura-Araxes horizon.

Next, in the Middle Bronze Age period (2200-1500 BC), there is an increase in steppe ancestry. The Y-DNA R1b-Z2103 and I2a2b appear associated with the Trialeti-Vanadzor culture. Apparently, those steppe pastoralists had a lower impact on northeastern parts of Georgia, likely due to the geography and high mountains. We see a preponderance of J2 there, while the southeastern regions of Kakhetia and regions bordering Armenia were more strongly affected by the steppe. This situation persists until the Iron Age 2 and Early Antique era (800-300 BC), when in the Urartian-Orontid period, we see a drop in steppe ancestry in Armenia. In Georgia, the drop in steppe ancestry was not abrupt but slow. This difference is another argument favoring the idea expressed in Petrosyan 2023 that this drop in Armenia is related to Urartu activities and post-Urartian events.

Starting from the Iron Age, the genetic histories of Armenia and Georgia begin to diverge. Georgia witnesses' migrations from the south in the Late Antique period to Early Medieval periods (1-400 AD). The authors link those migrants with the spread of Christianity but given that some of them appear in the 1st century AD (NAT004, 1950 ybp), we can assume they were related to the political events of that period. In the 1st century AD, Rome was trying to reinforce its control of Greater Armenia and the South Caucasian kingdoms of Iberia and Albania. Meanwhile, the Parthian Arsacids were trying to counteract them. As a result of these wars, the Arsacids became the rulers of Armenia and tried to impose their cadet branch in Iberia as well. Armenia on the other side gets a Levantine influence in Hellenistic period. From historic point of view, it is quite possible but given the small sample size and issues with models where various periods are not compared with the same source populations, there is a need of extra data to confirm this.

Starting from 400 AD, eastern Georgia witnesses new sporadic waves of migrants from the steppe, this time associated with the Huns and Sarmatians. My feeling is that the Maskut tribes' invasion is also associated with this event. These steppe intruders had a practice of artificial deformation of the skull, which the locals borrowed. The sample size from Armenia is small from those periods, which is probably why we don't see them in Armenia. Another possibility is that they didn't reach Armenia in large number. After the Middle Ages, there are no remarkable events.

Overall, this is a good paper that describes the genetic history of the region. This comparison would be more comprehensive if we had dense sampling of Armenia and Azerbaijan from the relevant periods. We should not forget that the sample size in the post-Urartian period Armenia is incomparable to what we have now from Georgia.

Besides the positive side there are some issues mentioned by other commentators:

- The choice of Iran_Chl as a source population instead of Iran_Neo. This choice can mask the Levant N ancestry present in the South Caucasus since the Neolithic period.

- Mentions of obsolete papers like Pagel 2013, where Pagel and Atkinson calculated the ages of divergence of different linguistic groups in Eurasia.

It must be noted that current genetic data do not forbid the deep origins of Kartvelian from CHG. Given that there was a resurgence of CHG in the Bronze Age Georgia corresponding to the age of divergence of Proto-Kartvelian.

The deep origin of PIE from local farmers is also still on the table. However, the most frequent Y-DNA of Kartvelian people (G2a1 from Fertile Crescent) and those in the CLV cline (R1b, from EHG) create other possibilities also. More data will obviously help us better understand the deep origins of Kartvelian and PIE.

See also

• Ancient Kartvelians and the Formation of Iberia

Two different stories in Anatolia

After the Neolithic period migrations from east changed the genetic landscape of plain Anatolia. Those migrations were not an one time event but two major events dated to different periods. It must be noted that in the current state of archaeologic knowledge there are no Neolithic sites in northern Anatolia. Food producing appear there in the Chalcolithic period which starts after the 5800 BCE. See the dividing line on the map.

Currently we have two Early Chalcolithic samples from Hattusa (Buyukkaya) in the north and Tell Kurdu in the south (the green circles on the map). They are dated to the same period after the 5800 BCE yet they have different shifts to east. The northern sample has a strong shift to east close to the Late Chalcolithic samples from the same place (Camlibel Tarlasi). While the southern site (Tell Kurdu) has a very little shift. In my previous thread dedicated to Aintab history I showed that in southern Anatolia the main migration from the east occurred at Late Chalcolithic, thus more than 1500 years later than in the north. Given that that those two events have a different archaeologic background then it's safe to assume that they are related to different ethnic groups.

Based on the currently available data we can link the Late Chalcolithic migrations in the south to the Minoans and IE Anatolians. While the northern Early Chalcolithic migration can be associated with Hattic people. This theory is supported by the strong presence of G2-M406 in Hattusan sites. While the same M406 was absent or rare in the Crete and Minoan civilization sites.

It's worth to note that in western Caucasus and Georgia the Neolithic settlements appear roughly in the same period. We can assume that the same impulse that introduced the food producing to north Anatolia moved also to western Georgia were a peculiar Neolithic culture emerged, different from the Shulaveri-Aratashen related sites in Kur-Araxian basin. Later those western Georgian farmers moved to north triggering the emergence of mountainous pastoralist culture known as Darkveti-Meshoko (after 4500BCE). We have samples from this latter culture. They are from a subbranch of J2-M67>CTS900. What linguistic group is related to the introduction of food producing to the west Caucasus is a more complex subject, which will be discussed later