3.5 | Maternal origin of Huaibei grey donkey
The molecular studies of the donkey mitochondrial sequence have apparently defined two distinct matriarchal (Clade Ⅰ and Ⅱ lineages) related to domestication. Comparison of the 60 reference mtDNA D-loop sequences (Table 5) and the HGD populations sequences of 418 bp were made to determine the relationships among the haplotypes and population structure of Huaibei grey donkey; the median joining network was constructed for the identified haplotypes. There are two distinct lineages (Clade Ⅰ and Clade Ⅱ) as shown in the median joining network, and most of the HGDs were classified into Clade Ⅰ (31 individuals [51.67%] and 4 haplotypes), whereas Clade Ⅱ included 29 individuals (48.33%) comprising 7 haplotypes (Figure 5).
To further clarify the origin of HGDs, we used mtDNA sequence comparisons with the Nubian wild ass (E. africanus africanus ), the Somali wild ass (E. africanus somaliensis ), Asian wild ass (E. hemionus ) , European and Chinese domestic donkeys. HGDs was clearly clustered within the Somali wild ass (E. africanus somaliensis ) sequences. They were clustered apart from the European and Chinese domestic donkey clade, as indicated in the phylogenetic tree, therefore these results indicate that Africa was the most probable location for donkey domestication (Figure 6).