Ancient DNA from Nubian and Somali wild ass provides insights into donkey ancestry and domestication

Abstract

Genetic data from extant donkeys (Equus asinus) have revealed two distinct mitochondrial DNA haplogroups, suggestive of two separate domestication events in northeast Africa about 5000 years ago. Without distinct phylogeographic structure in domestic donkey haplogroups and with little information on the genetic makeup of the ancestral African wild ass, however, it has been difficult to identify wild ancestors and geographical origins for the domestic mitochondrial clades. Our analysis of ancient archaeological and historic museum samples provides the first genetic information on the historic Nubian wild ass (Equus africanus africanus), Somali wild ass (Equus africanus somaliensis) and ancient donkey. The results demonstrate that the Nubian wild ass was an ancestor of the first donkey haplogroup. In contrast, the Somali wild ass has considerable mitochondrial divergence from the Nubian wild ass and domestic donkeys. These findings resolve the long-standing issue of the role of the Nubian wild ass in the domestication of the donkey, but raise new questions regarding the second ancestor for the donkey. Our results illustrate the complexity of animal domestication, and have conservation implications for critically endangered Nubian and Somali wild ass.

The function of zebra stripes

“…Subspecies information on the African wild ass was gleaned from ref. 57 and that on the kiang and Asiatic wild ass was gleaned from ref. 58.…”

Why the Donkey Did Not Go South: Disease as a Constraint on the Spread of Equus asinus into Southern Africa

“…3). Such overlap as may have existed (in western Djibouti, the lower Awash Valley and parts of the Somali Region of Ethiopia) would, in any case, only have been with the Somali subspecies of the wild ass (E. africanus somaliensis), which genetic analyses demonstrate is not ancestral to the domestic donkey and which last shared a common ancestor with donkeys and Nubian wild asses over 100,000 years ago (Kimura et al 2011).…”

“…Still further into the Sahara, donkeys were present in southwestern Libya by 1000 BC Fig. 1 Africa showing the location of the early archaeological occurrences of donkeys listed in Table 1 (Kimura et al 2011) and had expanded beyond the southern limits of the desert into the Sahel by the early centuries AD (MacDonald and MacDonald 2000). East of the Nile the Gash Delta has produced remains dated to the second millennium BC (Gautier and Van Neer 2006), broadly contemporary with representations of donkeys in the land of Pwnt (probably equivalent to the coast of northern Eritrea) in the reliefs of Queen Hatshepsut's funerary temple at Deir el-Bahri ca.…”

“…Clade I is closely related to the Nubian wild ass (E. africanus africanus), one of two surviving but genetically well-separated subspecies of the African wild ass (Beja-Pereira et al 2004;Kimura et al 2011). However, thus far, it has not been possible to establish the ancestry of clade II, except to exclude from consideration the other extant subspecies, the Somali wild ass (Equus africanus somaliensis) (Kimura et al 2011). This is consistent with a lack of evidence for this subspecies hybridising with domestic donkeys (Kebede 2013).…”

The Multi-dimensional Donkey in Landscapes of Donkey-Human Interaction

“…Archeologists add the dimension of time, with evidence that donkeys were native to the arid, stony deserts of north and north-eastern Africa (Beja-Pereira et al 2004), the original wild populations possibly extending into Arabia and the southern Levant (Kimura et al 2011). They were likely to have been first recruited for work in multiple separate locations.…”