| Donkey belongs to Equus genus.Although it has some traits similar to the horse,it performs much better tolerance to drought and pressure,which supports survival in extreme harsh environment.The domestication of donkey makes a major cultural shift away from fixed agricultural production model to a more mobile style in the human society.Therefore,it is important to human civilization.Nowadays,the wild ass is nearly extinct,accompanied with dramatic decline of donkey diversity.So it is imminent to clarify the evolution of donkey,which is prerequisite for conservation of genetic resource.Evidence from both mitochondrial DNA and archaeology concluded that donkey was domesticated in Northeastern African about 5000 years ago.Moreover,molecular evidence verified two donkey lineages :the Nubian lineage that was supposed to be raised from the Nubian wild asses,and the Somali lineage that originated from a relative of the exist Somali wild ass.For confirming further worldwide phylogeny of donkey,moreover,a globe perspective of genetic diversity,migration and demography of the two lineages is restricted.Therefore,we obtained sequences of the mitochondrial D-loop region from 113 samples(include donkey,Asian Wild ass,and horse)and whole mtDNA genome from 77 samples,which were then combined with a cohort of 531 mtDNA sequences download from NCBI for additional analysis.Combined those we built a standardized haplogroup tree of the donkey for the first time and related phylogeny tree.Besides,analysis on population structure of the two donkey lineages from different areas revealed that these are apparent discrepancy on median-joining network,diversity decay pattern,distribution in Africa and demographic history between the two lineages,suggesting different domestic history and independent migration.These results will support the conservation and utilization of donkey genetic resource and provide important clues on tracing the developmental history of ancient human civilization. |
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