PDA

View Full Version : The Arrival of Steppe and Iranian Related Ancestry in the Islands of the Western Mediterranean



Tacitus
03-21-2019, 09:09 PM
Shit, I was JUST talking about this paper in another thread today, not realizing it came out.
https://www.biorxiv.org/content/10.1101/584714v1

Abstract

A series of studies have documented how Steppe pastoralist-related ancestry reached central Europe by at least 2500 BCE, while Iranian farmer-related ancestry was present in Aegean Europe by at least 1900 BCE. However, the spread of these ancestries into the western Mediterranean where they have contributed to many populations living today remains poorly understood. We generated genome-wide ancient DNA from the Balearic Islands, Sicily, and Sardinia, increasing the number of individuals with reported data from these islands from 3 to 52. We obtained data from the oldest skeleton excavated from the Balearic islands (dating to ~2400 BCE), and show that this individual had substantial Steppe pastoralist-derived ancestry; however, later Balearic individuals had less Steppe heritage reflecting geographic heterogeneity or immigration from groups with more European first farmer-related ancestry. In Sicily, Steppe pastoralist ancestry arrived by ~2200 BCE and likely came at least in part from Spain as it was associated with Iberian-specific Y chromosomes. In Sicily, Iranian-related ancestry also arrived by the Middle Bronze Age, thus revealing that this ancestry type, which was ubiquitous in the Aegean by this time, also spread further west prior to the classical period of Greek expansion. In Sardinia, we find no evidence of either eastern ancestry type in the Nuragic Bronze Age, but show that Iranian-related ancestry arrived by at least ~300 BCE and Steppe ancestry arrived by ~300 CE, joined at that time or later by North African ancestry. These results falsify the view that the people of Sardinia are isolated descendants of Europe's first farmers. Instead, our results show that the island's admixture history since the Bronze Age is as complex as that in many other parts of Europe.

Voskos
03-21-2019, 09:34 PM
Awesome paper.And secondarily, finally some decent admixture model proving considerable carthage/phoenician ancestry in sicily.

SardiniaAtlantis
03-22-2019, 11:57 AM
It seems that Pausanias was right about Sardinia.

Peterski
03-22-2019, 12:02 PM
It's been known for a while that Sardinians have some Steppe but it is just a few % AFAIK. I haven't read this paper yet.

Imperator Biff
03-22-2019, 06:22 PM
This could explain the link between vasconic and paleosardinian.

sailormoon
03-22-2019, 06:46 PM
https://i.postimg.cc/FsfqTYmj/steppe.png
Figure 4: Proportions of ancestry using a distal qpAdm framework on an individual basis (a), andnbased on qpWave clusters (Fig. 3) (b).

Steppe ancestry in Early Bronze Age Sicily is estimated to be 23.3%-40.2% in the two outlier samples. The main Sicily_EBA cluster can be modeled with Steppe ancestry at 9.1 ± 2.3%. 4 of the 5 EBA Sicilian males had Steppe-associated Y-haplogroup R1b1a1a2a1a2.



We find evidence of Steppe ancestry in the Early Bronze Age by ~2200 BCE. In distal qpAdm, the outlier Sicily_EBA11443 is parsimoniously modeled as harboring 40.2 ± 3.5% Steppe ancestry, and the outlier Sicily_EBA8561 is parsimoniously modeled as harboring 23.3 ± 3.5% Steppe ancestry (Fig. 4a, Supplementary Table 9). The main Sicily_EBA cluster also can only be fit with Steppe ancestry albeit at a lower proportion of 9.1 ± 2.3%, and models without Steppe ancestry can be rejected (p=0.001) (Supplementary Table 9). The presence of Steppe ancestry in Early Bronze Age Sicily is also evident in Y chromosome analysis, which reveals that 4 of the 5 Early Bronze Age males had Steppe-associated Y-haplogroup R1b1a1a2a1a2.

Imperator Biff
03-22-2019, 07:20 PM
https://i.postimg.cc/FsfqTYmj/steppe.png
Figure 4: Proportions of ancestry using a distal qpAdm framework on an individual basis (a), andnbased on qpWave clusters (Fig. 3) (b).

Steppe ancestry in Early Bronze Age Sicily is estimated to be 23.3%-40.2% in the two outlier samples. The main Sicily_EBA cluster can be modeled with Steppe ancestry at 9.1 ± 2.3%. 4 of the 5 EBA Sicilian males had Steppe-associated Y-haplogroup R1b1a1a2a1a2.
Pretty much soundly debunks the idea steppe introgression into Sardinia came via roman colonists.
Steppe dna was more or less everywhere in Europe by the mid Bronze Age.

JQP4545
03-22-2019, 08:22 PM
The arrival of Iranian related ancestry into the Mediterranean during the Chalcolithic seems to be the migration that we know the least about. Who do you think brought this ancestry to Europe?

Imperator Biff
03-22-2019, 11:29 PM
The arrival of Iranian related ancestry into the Mediterranean during the Chalcolithic seems to be the migration that we know the least about. Who do you think brought this ancestry to Europe?

Later waves of CHG/Iran_N rich neolithic anatolians whom partially assimilated the earlier waves of EEF just before the IE migrations spread CHG dna across Europe. The distribution of haplogroup J2a correlates pretty well with this later Anatolian wave.

JQP4545
03-22-2019, 11:34 PM
Later waves of CHG/Iran_N rich neolithic anatolians whom partially assimilated the earlier waves of EEF just before the IE migrations spread CHG dna across Europe. The distribution of haplogroup J2a correlates pretty well with this later Anatolian wave.

Where did this come to Anatolia from? And is the Iranian ancestry related to the ancestry that spread to the Levant and North Africa?

Imperator Biff
03-23-2019, 12:30 AM
Where did this come to Anatolia from? And is the Iranian ancestry related to the ancestry that spread to the Levant and North Africa?

Neolithic Iranians came by way of the zagros mountains and they form a clade with CHG.
They were quite different from neolithic anatolians as ANF harboured some natufian dna (~15-20%) and had no ANE component. They are somewhat distantly related with the common dzudzuana affinity.