Analysis of mitochondrialDNAhaplogroup frequencies in the population of the slab burial mortuary culture of Mongolia (ca. 1100–300 BCE)
Authors: Rogers Leland Liu , Kaestle Frederika Ann 
Published: February 2022

Recent research has shown evidence of ancient admixture from both eastern and western Eurasian genetics in the human populations of Mongolia going back to at least the Eneolithic Afanasievo archaeological culture (ca. 3000 BCE). Eastern mtDNA lineages found in ancient and living Mongolians in the past and present have greatest affinity with Neolithic populations from the Transbaikal region of southern Siberia, suggesting that people from this region were likely the first to colonize northern and eastern Mongolia after the last glacial maximum (ca. 24,500–17,000 BCE), while western Eurasian groups probably migrated to the steppe in association with the earliest forms of pastoralism. While some studies suggest the contribution of these ancient western lineages to the modern populations in Mongolia was minimal, this research demonstrates that western mtDNA lineages were particularly prominent among the burial populations of the Early Iron and Iron Ages in the region. This is most notable among the burial population associated with slab burials and the burial population of their successors, the people associated with the Xiongnu polity (209 BCE–91 CE). Similarities between mtDNA haplogroup frequencies of the slab burial and Xiongnu burial populations also strongly support the proposal that the builders of the slab burials were the principal ancestors of the Xiongnu people.

Objectives

The objective of this research is to increase understanding of human population change on the Mongolian steppe during the first millennium BCE and how it may be associated with cultural change and the creation of early eastern steppe empires. It examines the mtDNA haplogroup frequencies of the burial population from slab burials in Mongolia and compares it with frequencies from various other populations to determine population affinities.

Methods

This study was primarily based on Sanger sequencing the HV1 of the mtDNA of ancient individuals from Mongolia during the Early Iron Age for haplogroup determination and then comparing mtDNA haplogroup frequencies with previously published data including 110 ancient and modern populations. The 21 samples used in this study were selected based on region, dating, and availability. Pairwise Fsts of mtDNA haplogroup frequencies were calculated using the Arlequin population genetics program.

Results

The mtDNA hg of 20 of 21 samples are determined and added to previously published data, increasing the total sample to 35 for the particular population of interest. Using this mtDNA gene pool, it is determined that by the Late Bronze Age an east–west mixed population has already been established, which stays relatively stable into the Iron Age (Xiongnu) period, suggesting that the people practicing the slab burial tradition are the most likely biological ancestors of the Xiongnu. It also notes a distinct difference in mtDNA haplogroup frequencies between north‐eastern and central populations in Mongolia during the Iron Age.

Conclusions

There was little change in mtDNA haplogroup frequencies during the first millennium BCE, which contrasts with the clear change in the first millennium CE. MtDNA hg frequencies (matrilines) seemed to be stable at around 28%; however, Y‐ch frequencies have a dramatic shift towards western lineages during the Xiongnu period (300 BCE–200 CE). The mtDNA haplogroup frequencies from the population from the slab burials have close affinity with the Xiongnu population frequencies. This suggests a notable and consistent western Eurasian component in Mongolia during the first millennium BCE, established before the end of the Bronze Age and possibly associated with the introduction of the domestic horse.