The Complete Mitochondrial Genome Sequence Analysis Of Equus From Yan Jialiang Site In Baotou

Yan Jialiang site is located in yan Jialiang village,Jiuyuan District,Baotou City,Inner Mongolia Autonomous Region.According to archaeologists,it should be a land and river post site of Yuan Dynasty with great cultural significance.Its excavation and discussion provide multiple ways for us to understand the post station system,traffic situation and economic characteristics.Archaeologists found many roads,ash pits,house sites,hoards,tombs and other relics at the site,and unearthed many relics such as porcelain,iron and copper.At the same time,many human and animal bones were excavated.The species and genera of animal bone samples include pigs,cattle,goats,dogs,camels,horses and donkeys,including 463 horse bone samples and 82 donkey bone samples.In this paper,DNA extraction and sequencing were carried out on 13 ancient horse bone specimens and 2 ancient donkey bone specimens unearthed from yanjialiang site.The mitochondrial whole genome sequences of 10 Yuan Dynasty horses and 2 Yuan Dynasty donkeys were successfully extracted.For these 12 sequences,we carried out mitochondrial whole genome analysis.First,Download 100 mitochondrial genome sequences of horses(14 in ancient times and 86 in modern times)and 25 mitochondrial genome sequences of donkeys(3in ancient times and 22 in modern times)from Gen Bank.Then,a total of 137 sequences including yanjialiang samples were constructed.The results showed that the individuals of donkey and horse were clearly distinguished,which was consistent with the morphological identification.The maximum likelihood tree and Bayesian tree were established for the complete mitochondrial sequences of 110 horses,and the maximum likelihood tree and Bayesian tree were established for the sequences of 27 donkeys.The results showed that 10 ancient horses in Yan Jialiang site had five haplotypes: B,G,l,Q and R.It is certain that YJL01 H has a close genetic relationship with Chinese native horses such as modern Yili horse and Yanqi horse;YJL02H has a close genetic relationship with an ancient Mongolian horse and two modern European horses;YJL05H is closely related to an Arabian horse;YJL06H is close to an Iranian modern horse;YJL07H has a close genetic relationship with an ancient horse on the ukok plateau in the7 th century BC;YJL09H is closely related to an Iranian modern horse and a European modern horse,and YJL10 H is closely related to a Yakutian horse and a Syrian modern horse.Through the phylogenetic analysis of the complete sequences of ancient donkeys in Yan Jialiang site and other 25 sequences,it is known that the two ancient donkeys in yanjialiang can belong to lineage I and Lineage II respectively,and YJL16 D has a very close genetic relationship with an ancient donkey in Xi'an,Shaanxi Province;YJL17D is closely related to a modern Kenyan donkey.Subsequently,we downloaded the mitochondrial control region sequences of 499 horses from Gen Bank and established the maximum likelihood tree and intermediary network diagram together with the mitochondrial control region sequences of 8 ancient horse samples in Yan Jialiang.It was found that according to the classification of mitochondrial control region,Yan Jialiang ancient horses can be divided into A,D,F and G four lineages.The horses represented by YJZ02 at Yu Jiazhuang site in Ningxia may be the ancestors of YJL01 H,YJL07H and YJL08H;YJL02H,YJL06 H and YJL12 H gather with many modern European horses,have maternal genetic relationship,this may be related to the foreign exchange function of Yan Jialiang as a post station;YJL09H has close genetic relationship with Xin Dianzi site,Xiao Shuanggucheng site and an ancient European horse in the 9th century;YJL05H gathers with ancient horse from the Xiao Shuanggucheng site and some modern European horses;YJL10H is closely related to a Moldovan ancient horse,a mustang and an ancient horse of Da Shanqian site;YJL11H may have a source relationship with the ancient horse of Bancheng sites and two ancient horses from Siberia.Maternal genetic diversity is cast by many reasons.First,Yan Jialiang site is located in the south of Kundulun Valley,close to the Yellow River.Its geographical location is very special,and the post system of the Yuan Dynasty is complete.Many land and water post stations have been set up along the Yellow River,which greatly promoted the economic and cultural exchanges between China and the West,created the prosperity of yanjialiang site in the Yuan Dynasty,and also contributed to the genetic diversity of ancient horse matrilineal in yanjialiang.Second,the Yuan Dynasty originated from the grassland culture.It was good at controlling and breeding horses,and had a complete horse administration system.It would introduce excellent horse varieties and promote the diversity of maternal genetics.Third,the rulers of the Yuan Dynasty were good at war and obtained many excellent horse breeds in the process of war,which promoted the diversity of genetic information.