Ancient DNA provides clues to donkey domestication

Proceedings of the Royal Society B doi: 10.1098/rspb.2010.0708

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

Birgitta Kimura et al.

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.

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Domestication of the donkey

The EurekAlert press release:

An international group of researchers has found evidence for the earliest transport use of the donkey and the early phases of donkey domestication, suggesting the process of domestication may have been slower and less linear than previously thought.

Based on a study of 10 donkey skeletons from three graves dedicated to donkeys in the funerary complex of one of the first Pharaoh's at Abydos, Egypt, the team, led by Fiona Marshall, Ph.D., professor of Anthropology at Washington University in St. Louis, and Stine Rossel of the University of Copenhagen, found that donkeys around 5,000 years ago were in an early phase of domestication. They looked like wild animals but displayed joint wear that showed that they were used as domestic animals.

“Genetic research has suggested African origins for the donkey,” said Marshall. “But coming up with an exact time and location for domestication is difficult because signs of early domestication can be hard to see. Our findings show that traces of human management can indicate domestication before skeletal or even genetic changes."

The previously unpublished research was presented in “Domestication of the Donkey: New Data on Timing, Process and Indicators” in the March 10 online edition of the Proceedings of the National Academy of Sciences.

Domestication of the donkey from the African wild ass was a pivotal point in human history. It transformed ancient transport systems in Africa and Asia and the organization of early cities and pastoral societies.

The research team examined the 5,000-year-old Abydos skeletons along with 53 modern donkey and African wild ass skeletons. Analysis showed that the Abydos metacarpals were similar in overall proportions to those of wild ass, but individual measurements varied. Mid-shaft breadths resembled wild ass, but mid-shaft depths and distal breadths were intermediate between wild ass and domestic donkey.

Despite this, all the Abydos skeletons exhibited a range of wear and other pathologies on their bones consistent with load carrying. Morphological similarities to wild ass show that despite their use as beasts of burden, donkeys were still undergoing considerable phenotypic change during the early dynastic period in Egypt. This pattern is consistent with recent studies of other domestic animals that suggest that the process of domestication is slower and more complicated than had been previously thought.

Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0709692105

Domestication of the donkey: Timing, processes, and indicators

Stine Rossel et al.

Abstract

Domestication of the donkey from the African wild ass transformed ancient transport systems in Africa and Asia and the organization of early cities and pastoral societies. Genetic research suggests an African origin for the donkey, but pinpointing the timing and location of domestication has been challenging because donkeys are uncommon in the archaeological record and markers for early phases of animal domestication are hard to determine. We present previously undescribed evidence for the earliest transport use of the donkey and new paleopathological indicators for early phases of donkey domestication. Findings are based on skeletal data from 10 {approx}5,000-year-old ass skeletons recently discovered entombed in an early pharaonic mortuary complex at Abydos, Middle Egypt, and a concurrent study of 53 modern donkey and African wild ass skeletons. Morphometric studies showed that Abydos metacarpals were similar in overall proportions to those of wild ass, but individual measurements varied. Midshaft breadths resembled wild ass, but midshaft depths and distal breadths were intermediate between wild ass and domestic donkey. Despite this, all of the Abydos skeletons exhibited a range of osteopathologies consistent with load carrying. Morphological similarities to wild ass show that, despite their use as beasts of burden, donkeys were still undergoing considerable phenotypic change during the early Dynastic period in Egypt. This pattern is consistent with recent studies of other domestic animals that suggest that the process of domestication is slower and less linear than previously thought.

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