Origins of Chinese reindeer (Rangifer tarandus) based on mitochondrial DNA analyses

Abstract

The most southern population of reindeer (Rangifer tarandus) inhabits northeastern China, but the migration route and origin of this population have not been confirmed. The sequences of mitochondrial DNA control regions from domestic and wild herds from Eurasia and China were analysed. The results showed that the Chinese reindeer population originated independently from north-central Russian domestic herds, belonging to a large reindeer population that was present across Beringia during the last glacial period. Some studies have reported that the Chinese reindeer population is closely related to wild forest reindeer herds in Russia. Our results, however, indicate that wild forest reindeer herds of southeastern Russia contributed little or nothing to the Chinese reindeer herd gene pool. Chinese reindeer herds have a much greater genetic similarity to more northerly distributed tundra-type herds that inhabit open areas. The present findings will be essential for future conservation planning for Chinese reindeer.

Fig 1. Distribution of Rangifer tarandus sampled from eight geographical regions in China.

The eight reindeer clusters are detailed in Table 1,and the haplotypes in the pie chart are colored according to the haplogroup classification in Fig 3A. Pale-yellow are on the map indicates the distribution range of Chinese reindeer, which can be found in Fig 3B.

Fig 2. Bayesian phylogenetic tree reconstruction.

Bayesian phylogenetic tree reconstruction using mitochondrial control region haplotypes. The coloured branches represent the haplogroups (blue = A1, green = A2, grey = A3, red = A4). The haplotypes marked in red were found only in Chinese reindeer populations. Node values = BPP×100%, only node values≥0.75 are indicated.

Fig 3

(a) Median-joining network for mitochondrial DNA haplotypes found in Chinese reindeer. The five different haplotype clusters (haplogroups, A1-A4 & 0) are encircled with different colours. The circles represent haplotypes, and the circle sizes are proportional to the haplotype frequencies. (b) Haplogroup frequencies in wild (squares) and domestic (triangles) reindeer herds. The populations were pooled according to geography and whether they were wild or domestic herds. (1) Northeastern China; (2) north-central Russian domestic; (3) northwestern Russian domestic; (4) Finland wild; (5) Finland domestic; (6) Norway wild; (7) Norway domestic; (8) northeastern Russian domestic; (9) northeastern Russian wild; (10) southeastern Russian wild; (11) southeastern Russian domestic.

Fig 4. Median-joining tree.

Median-joining tree of the mtDNA control region haplotypes identified in this study. The circles represent haplotypes, and the circle sizes are proportional to haplotype frequencies. The circles are coloured according to the haplogroup membership locations.