The diverse genetic origins of a Classical period Greek army

 

https://www.pnas.org/doi/10.1073/pnas.2205272119

Here, we analyze genome-wide data from 33 individuals associated with the Battles of Himera and from Himera’s civilian population, as well as 21 individuals from two nearby settlements associated with the indigenous Sicani culture of Sicily, to provide insight into the genetic ancestry of Sicily’s inhabitants in the first millennium BCE and to provide additional data points for evaluating the role of ancient conflict in population interactions in the ancient Mediterranean.

Using qpAdm, this group (Sicily_IA, new data) can be modeled as an admixture of four sources that distantly contributed to the genetic composition of Europeans (P = 0.179): 

Northwestern Anatolian Neolithic farmers (Turkey_Barcin_N; 76.4 ± 1.2%), WHGs (6.4 ± 1.0%), early farmers from Iran (Iran_GanjDareh_N; 6.3 ± 1.5%), and Early Bronze Age (EBA) Steppe herders associated with the Yamnaya cultural complex (Russia_Samara_EBA_Yamnaya; 10.9 ± 1.6%), which indicates an increase of Iranian-related admixture compared with the preceding LBA Sicily group, which can be best modeled without that component. One line of evidence for some local genetic continuity is the almost exclusive presence of Y-chromosomal haplogroup G-Z1903 and its derivates among the males.

Most Himerans associated with the battles can be found clustering on the PCA closely with individuals from the Greece_LBA, consistent with a major contribution of individuals of primarily Greek ancestry in the Himeran forces and substantial genetic continuity between the LBA period in Greece and fifth-century-BCE Greek colonies in Sicily.  Seven of the 16 soldiers of the 480 BCE battle (Sicily_Himera_480BCE_1) and all 5 of the soldiers of the 409 BCE battle (Sicily_Himera_409BCE) are part of this main genetic cluster. Using the qpWave/qpAdm framework, we can model each of the soldiers in these two groups as deriving their ancestry either 100% from a group related to Greece_LBA or from an admixture between a Sicilian LBA or IA source and an Aegean-related source 

One irritating thing about this unsupervised ADMIXTURE run is they label the Euro HG component as WHG and not EHG. This will obviously have funny results when trying to find non-local ancestry, especially from Northeastern Europe or the Steppes, like Baltic_IA showing up as 50% "WHG"

Looks like the non-outlier Himerian soldiers can be modelled as a mix of Aegean_BA + Sicily_LBA/IA, somewhat bolstering the idea that these Himerians were descendants of Greek colonists mixed with the local Sicilians.

Two individuals (I10943/W0396 and I10949/W0403; Sicily_Himera_480BCE_3) fall with modern northeastern European groups and eastern Baltic populations of the first millennium BCE and can be modeled using exclusively BA individuals from Lithuania as a proxy source (P = 0.129). 

 One low-coverage individual, I17870/W0336, falls intermediate between Sicily_Himera_480BCE_2 and Sicily_Himera_480BCE_3 on both PCA and with respect to the main ancestry clusters inferred from ADMIXTURE. 

Two (I10944/W0461 and I10947/W1774; Sicily_Himera_480BCE_4) fall with individuals from IA nomadic contexts in the Eurasian Steppe. In qpAdm, their ancestry is consistent, with around 85–89% deriving from IA Central steppe nomads and 11–15% from an Aegean-like source, an admixture that plausibly could have taken place among the genetically diverse populations of the Steppe. Their mitochondrial DNA (mtDNA) haplogroups suggest east Eurasian genetic roots: A6a, found so far only in modern-day China (70, 71), and N1a1a1a, restricted to Russia, Kazakhstan, and Mongolia. 

Finally, one outlier (I10951/W0653; Sicily_Himera_480BCE_5) falls with modern Caucasus populations and intermediate to ancient Steppe and Caucasus individuals on the PCA and carries the highest proportion of the CHG component in ADMIXTURE (Fig. 2). A single one-way model with a group closely related to Armenia_MBA as the source fit the data (P = 0.293). Similarly, the second low-coverage individual, I17872/W0428, falls closest to populations from the Caucasus on the PCA .

Now, for the outliers.. Won't be surprised if I10944 and I10947 were Sarmatians, they have the typical East Eurasian mtDNA plus slight East Asian DNA (10-15%) in amounts typical of Sarmatians and Cimmerians.

All the soldiers who fall outside the Aegean genetic cluster are interred in mass graves Nos. 1–4 (SI Appendix, Figs. S1–S3), whereas all individuals from mass graves Nos. 5–7 (SI Appendix, Figs. S4–S6) fall within this cluster, a statistically significant difference (P = 0.0028 by a χ2 test with one degree of freedom; Fig. 3). This result mirrors strontium isotope evidence showing more nonlocals interred in mass grave.  Mass graves Nos. 1–4 and Nos. 5–7 also are spatially segregated and differ in size, with mass graves Nos. 1–4 comprising significantly more interments. 

Furthermore, individuals in mass graves Nos. 5 and 6 include grave goods, unlike the other mass graves from 480 BCE (32). The fact that these individuals also fall within the Aegean genetic cluster suggests a link between Aegean ancestry and prestige, as perceived by the individuals responsible for burying the fallen soldiers.

Individuals with “foreign” ancestry, all of whom also are identified as nonlocal on the basis of isotopic evidence (Fig. 3 and Dataset S2), were interred in larger mass graves Nos. 1–4, and individuals with genetic affinities to other Greek populations were interred in the smaller mass graves Nos. 5–7

It looks like the local soldiers, who were of Aegean descent, were given more prestigious burials than the non-local ones.