Mitochondrial DNA Footprints from Western Eurasia in Modern Mongolia

Abstract

Mongolia is located in a strategic position at the eastern edge of the Eurasian Steppe. Nomadic populations moved across this wide area for millennia before developing more sedentary communities, extended empires, and complex trading networks, which connected western Eurasia and eastern Asia until the late Medieval period. We provided a fine-grained portrait of the mitochondrial DNA (mtDNA) variation observed in present-day Mongolians and capable of revealing gene flows and other demographic processes that took place in Inner Asia, as well as in western Eurasia. The analyses of a novel dataset (N = 2,420) of mtDNAs highlighted a clear matrilineal differentiation within the country due to a mixture of haplotypes with eastern Asian (EAs) and western Eurasian (WEu) origins, which were differentially lost and preserved. In a wider genetic context, the prevalent EAs contribution, larger in eastern and central Mongolian regions, revealed continuous connections with neighboring Asian populations until recent times, as attested by the geographically restricted haplotype-sharing likely facilitated by the Genghis Khan’s so-called Pax Mongolica. The genetic history beyond the WEu haplogroups, notably detectable on both sides of Mongolia, was more difficult to explain. For this reason, we moved to the analysis of entire mitogenomes (N = 147). Although it was not completely possible to identify specific lineages that evolved in situ, two major changes in the effective (female) population size were reconstructed. The more recent one, which began during the late Pleistocene glacial period and became steeper in the early Holocene, was probably the outcome of demographic events connected to western Eurasia. The Neolithic growth could be easily explained by the diffusion of dairy pastoralism, as already proposed, while the late glacial increase indicates, for the first time, a genetic connection with western Eurasian refuges, as supported by the unusual high frequency and internal sub-structure in Mongolia of haplogroup H1, a well-known post-glacial marker in Europe. Bronze Age events, without a significant demographic impact, might explain the age of some mtDNA haplogroups. Finally, a diachronic comparison with available ancient mtDNAs made it possible to link six mitochondrial lineages of present-day Mongolians to the timeframe and geographic path of the Silk Route.

Genetic structure and differentiation from early bronze age in the mediterranean island of sicily: Insights from ancient mitochondrial genomes

“…All mtDNA haplotypes were classified into haplogroups using Haplogrep 2.0 (Weissensteiner et al, 2016) according to the most up-to-date mtDNA phylogeny, as reported in PhyloTree build 17 (http:// www.phylotree.org/) (van Oven and Kayser, 2009). The consistency of haplogroup classifications based on controlregion and full mitogenome data in Eurasian populations have been confirmed in recent papers (Modi et al, 2020;Cardinali et al, 2022). A diachronic comparison between modern and ancient individuals was achieved through a principal component analysis (PCA) based on haplogroup frequencies (Supplementary Table S5) and conducted by employing the function fviz_pca_ biplot from the R-package factoextra (Kassambara and Mundt, 2017).…”

The Revolution of Animal Genomics in Forensic Sciences

“…Nowadays, the extensive mtDNA typing of population data and the establishment of dedicated databases such as EMPOP (www.empop.org) provide as many as possible mitogenomes at a maximum level of resolution and quality. Phylogeographic investigations conducted on local populations distributed worldwide ( [61][62][63][64] as examples) constantly contribute toward the definition of reference population databases to be used at a microgeographic level. A branch of forensic genetics that frequently uses mitochondrial polymorphisms in conjunction with DNA barcoding is wildlife forensics, which deals with crimes perpetrated against protected species.…”

Helena’s Many Daughters: More Mitogenome Diversity behind the Most Common West Eurasian mtDNA Control Region Haplotype in an Extended Italian Population Sample

“…In West Eurasian populations, the most common mtDNA CR haplotype (MCH) falls into haplogroup H—poetically referred to as “Helena” [ 7 ]—and its close relatives. It is characterized by the mutational motif 263G 315.1C 16519C relative to the revised Cambridge reference sequence (rCRS) [ 8 ] and is found at a frequency of ~3–4% throughout West Eurasia [ 9 ], and in populations of European origin [ 10 ], with only slightly lower proportions at the far extensions of West Eurasian populations [ 11 ].…”