Genetics of Liqian People

"With the widespread population movements documented in the study, it is intriguing to see the degree of genetic continuity that has been maintained in Xinjiang over the past 5000 years." said Associate Prof. Vikas Kumar from IVPP, the first author of this study.

"What is striking about these results is that the demographic history of a cross-roads region as Xinjiang has been marked not by population replacements, but by the genetic incorporation of diverse incoming cultural groups into the existing population, making Xinjiang a true 'melting-pot,'" said Prof. Fu.

This detailed aspect had not been so clear looking only at archeological and cultural evidence. These findings suggest the importance of combining genetic and archeological evidence to provide a more comprehensive insight into population history.

The current ancient DNA analysis highlights a holistic approach to unraveling the complex history of locations like Xinjiang, where the many interactions between different groups and cultures in the past make detailed demographic studies difficult. Future studies in this area could reveal more about the finer points of Xinjiang's history.



Bronze and Iron Age population movements underlie Xinjiang population history

5000 years of Xinjiang genetics
The Xinjiang region of China is bordered by mountains and represents an important historical region. Sampling ancient genomes, Kumar et al. investigated the changes in populations of this region over time from the Bronze Age, ~5000 to 3000 years before the present (BP), covering the Iron Age, ~3000 to 2000 years BP, and into the Historical Era, ~2000 years BP. This analysis identified that older individuals represented ancestries from Steppe cultures, and that a later inflow of East and Central Asian ancestry entered the region around the end of the Bronze Age toward the beginning of the Iron Age. During the Historical Era, mixing continued but retained a core Steppe component such that populations form a genetic continuum. This retention of genetic continuity in a central population is surprising because it represents patterns more typically observed in isolated populations. Furthermore, these genetic links identify a previously unknown lineage that could potentially explain the spread of the Indo-European languages. —LMZ

Abstract
The Xinjiang region in northwest China is a historically important geographical passage between East and West Eurasia. By sequencing 201 ancient genomes from 39 archaeological sites, we clarify the complex demographic history of this region. Bronze Age Xinjiang populations are characterized by four major ancestries related to Early Bronze Age cultures from the central and eastern Steppe, Central Asian, and Tarim Basin regions. Admixtures between Middle and Late Bronze Age Steppe cultures continued during the Late Bronze and Iron Ages, along with an inflow of East and Central Asian ancestry. Historical era populations show similar admixed and diverse ancestries as those of present-day Xinjiang populations. These results document the influence that East and West Eurasian populations have had over time in the different regions of Xinjiang.

More information: Vikas Kumar et al, Bronze and Iron Age population movements underlie Xinjiang population history, Science (2022). DOI: 10.1126/science.abk1534. www.science.org/doi/10.1126/science.abk1534
Journal information: Science

Phenotypic analysis of several remains, the first reported for ancient Xinjiang, gave depth to the genetic results. The majority of individuals investigated had dark brown to black hair and brown eye color throughout Bronze Age, Iron Age, and HE. Corresponding with the appearance of Andronovo Steppe ancestry, a small proportion of the Iron Age individuals are marked by blond hair, blue eyes and lighter skin tone in the west and north of Xinjiang. Two Early Bronze Age Tarim Basin mummies in east Xinjiang were found likely to have had dark brown to black hair and darker skin, despite their archeologically-identified "western" features, and a more recent third mummy from the Late Bronze Age was likely to have had a more intermediate skin tone.


Fig. S30. Phenotypic analysis of hair color for Xinjiang samples using HIrisPlex-S. Predicted hair color given as a probability of either black, brown, blonde, or red for samples having a minimum depth of 5x for each covered SNP. Samples grouped in boxes according to time period: black, BA (5000-3500 BP); gray, LBA (3500-3000 BP); orange, IA (3000-2000 BP); purple, HE (<2000 BP). Blank boxes denote a lack of available samples or lack of samples passing depth threshold for that time period. Samples for the Xiaohe site from Zhang et al. 2021 (16) are indicated with a gray circle above them and are predicted at a lower minimal depth of 3x for each covered SNP. Prediction accuracies as expressed by the area under the curve of a receiver operating characteristic curve (AUC) are given in Table S15.




Fig. S31. Phenotypic analysis of skin tone for Xinjiang samples using HIrisPlex-S. Predicted skin tone given as a probability of either dark to black, dark, intermediate, pale, or very pale for samples having a minimum depth of 5x for each covered SNP. Samples grouped in boxes according to time period: black, BA (5000-3500 BP); gray, LBA (3500-3000 BP); orange, IA (3000-2000 BP); purple, HE (<2000 BP). Blank boxes denote a lack of available samples or lack of samples passing depth threshold for that time period. Samples marked with a gray circle are from Zhang et al. 2021 (16) and are predicted at a lower minimal depth of 3x for each covered SNP. Prediction accuracies as expressed by the area under the curve of a receiver operating characteristic curve (AUC) are given in Table S14. Images of skin color categories can be found in Chaitanya et al. (36).