A new study reveals that the DNA of the dromedary, the one-humped Arabian camel, was shaped by human migrations. This animal has been used in North Africa and Asia for transportation for thousands of years and was integral in the success of human societies in environments that would otherwise be inhospitable.
"Many open questions remain with regard to the dromedary's domestication and evolutionary history," said Pamela Burger from Vetmeduni Vienna and senior author of the study. "We have managed to turn the wild dromedary into a domesticate, but we don't know how and where domestication began and what effect it has had on today's animals."
Although domestication typically consists of breeding animals with the most beneficial genotypes, Burger and her team reveal that this is not the case with the dromedary. These unique animals possess a great degree of genetic diversity and yet breeding typically results in low genetic diversity, separating them from other animals that were domesticated using the breeding process.
After collecting samples from almost 1,100 extant dromedaries, the team used DNA analysis to compare them with samples obtained from archaeological samples from wild and early-domesticated animals.
The results revealed a direct connection between the Arabian camel's genetic diversity and its use as a transport animal. Their back-and-forth movement brought various populations into contact with one another, resulting in gene flow that fostered genetic diversity. However, this diversity makes it difficult to determine where the dromedary originated and thus was first domesticated.
After analyzing up to 7,000-year-old DNA from the bones of both wild and early-domesticated dromedaries, Burger and her Vetmeduni Vienna team compared results with modern dromedary DNA and determined that the first domestication of the Arabian camel took place in the Southeast Arabian Peninsula.
"Our results appear to confirm that the first domestication of wild dromedaries occurred on the southeast coast," she said. "This was followed by repeated breeding of wild dromedaries with the early-domesticated populations."
The wild ancestor of today's domesticated Arabian camels were limited in terms of their geographic range and went extinct approximately 2,000 years after domestication began.
The findings were published in the May 9 issue of the Proceedings of the National Academy of Sciences.
