title: Ancient DNA provides new insight into the maternal lineages and domestication of Chinese donkeys.
abstract: BACKGROUND
  The donkey (Equus asinus) is an important domestic animal that provides a reliable source of protein and method of transportation for many human populations. However, the process of domestication and the dispersal routes of the Chinese donkey are still unclear, as donkey remains are sparse in the archaeological record and often confused with horse remains. To explore the maternal origins and dispersal route of Chinese donkeys, both mitochondrial DNA D-loop and cytochrome b gene fragments of 21 suspected donkey remains from four archaeological sites in China were amplified and sequenced.
  
  
  RESULTS
  Molecular methods of species identification show that 17 specimens were donkeys and three samples had the maternal genetic signature of horses. One sample that dates to about 20,000 years before present failed to amplify. In this study, the phylogenetic analysis reveals that ancient Chinese donkeys have high mitochondrial DNA diversity and two distinct mitochondrial maternal lineages, known as the Somali and Nubian lineages. These results indicate that the maternal origin of Chinese domestic donkeys was probably related to the African wild ass, which includes the Nubian wild ass (Equus africanus africanus) and the Somali wild ass (Equus africanus somaliensis). Combined with historical records, the results of this study implied that domestic donkeys spread into west and north China before the emergence of the Han dynasty. The number of Chinese domestic donkeys had increased primarily to meet demand for the expansion of trade, and they were likely used as commodities or for shipping goods along the Silk Road during the Tang Dynasty, when the Silk Road reached its golden age.
  
  
  CONCLUSIONS
  This study is the first to provide valuable ancient animal DNA evidence for early trade between African and Asian populations. The ancient DNA analysis of Chinese donkeys also sheds light on the dynamic process of the maternal origin, domestication, and dispersal route of ancient Chinese donkeys.
authors.affiliation: Key-Lab for Evolution of Past Life and Environment in Northeast Asia, Jilin University, Ministry of Education, Changchun, 130012, PR China. luhan@jlu.edu.cn.|Ancient DNA Laboratory, School of Life Sciences, Jilin University, Changchun, 130012, PR China. luhan@jlu.edu.cn.|Research Center for Chinese Frontier Archaeology, Jilin University, Changchun, 130012, PR China. luhan@jlu.edu.cn.
authors.forename: Lu
authors.initials: L
authors.lastname: Han
authors.affiliation: Ancient DNA Laboratory, School of Life Sciences, Jilin University, Changchun, 130012, PR China. songbiao_zhu@163.com.
authors.forename: Songbiao
authors.initials: S
authors.lastname: Zhu
authors.affiliation: Ancient DNA Laboratory, School of Life Sciences, Jilin University, Changchun, 130012, PR China. ningchao.jlu@gmail.com.
authors.forename: Chao
authors.initials: C
authors.lastname: Ning
authors.affiliation: Research Center for Chinese Frontier Archaeology, Jilin University, Changchun, 130012, PR China. caidw@jlu.edu.cn.
authors.forename: Dawei
authors.initials: D
authors.lastname: Cai
authors.affiliation: Ancient DNA Laboratory, School of Life Sciences, Jilin University, Changchun, 130012, PR China. fallenanglewk@163.com.
authors.forename: Kai
authors.initials: K
authors.lastname: Wang
authors.affiliation: Research Center for Chinese Frontier Archaeology, Jilin University, Changchun, 130012, PR China. chenquanjia123@163.com.
authors.forename: Quanjia
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Archaeological Research Institute of Shaanxi Province, Xi' an, 710054, PR China. husongmei@sina.com.
authors.forename: Songmei
authors.initials: S
authors.lastname: Hu
authors.affiliation: Institute for Archaeology and Relic Conservation of Xi' an, Xi' an, 710068, PR China. 617084336@qq.com.
authors.forename: Junkai
authors.initials: J
authors.lastname: Yang
authors.affiliation: Archaeological Research Institute of Shaanxi Province, Xi' an, 710054, PR China. shaojing-0521@163.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Shao
authors.affiliation: Key-Lab for Evolution of Past Life and Environment in Northeast Asia, Jilin University, Ministry of Education, Changchun, 130012, PR China. zhuhong@jlu.edu.cn.|Research Center for Chinese Frontier Archaeology, Jilin University, Changchun, 130012, PR China. zhuhong@jlu.edu.cn.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Key-Lab for Evolution of Past Life and Environment in Northeast Asia, Jilin University, Ministry of Education, Changchun, 130012, PR China. zhouhui@jlu.edu.cn.|Ancient DNA Laboratory, School of Life Sciences, Jilin University, Changchun, 130012, PR China. zhouhui@jlu.edu.cn.|Research Center for Chinese Frontier Archaeology, Jilin University, Changchun, 130012, PR China. zhouhui@jlu.edu.cn.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhou
mesh_terms: D000818:Animals; D000829:Animals, Domestic; D001106:Archaeology; D002681:China; D045303:Cytochromes b / Q000235:genetics; D004272:DNA, Mitochondrial / Q000032:analysis / Q000235:genetics*; D018397:Equidae / Q000145:classification* / Q000235:genetics*; D006736:Horses / Q000235:genetics; D008928:Mitochondria / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny
chemical_list: D004272:DNA, Mitochondrial; D045303:Cytochromes b