Camels, the “ships of the desert”, remained genetically diverse despite domestication precisely because they were used to travel such long distances, a new study of modern and ancient camel DNA has found.
Domestication also probably saved the animals from extinction, the research concluded.
Ancient caravan routes gave Arabian camels, or the one-humpred dromedary, the opportunity to interbreed with animals hundreds of kilometres away, rather than mating within a restricted gene pool close to home.
The study sheds light on the evolutionary history and domestication of the animals which, despite their widespread use for the past 3,000 years, has until now been hazy.
“In contrast to other livestock species, the evolutionary history and domestication of Old World camelids have remained largely unexplored because of the scarcity of camel bone assemblages from well-dated archaeological contexts,” the authors write in the study published in PNAS.
The study analysed the DNA of almost 1,100 modern dromedaries, from across the species’ range, and compared that to samples of ancient DNA up to 7,000 years old from wild and early-domesticated camels.
The researchers found substantial shared genetic variation in modern camel populations except for one genetically distinct camel population that had been isolated in Eastern Africa.
It appears that domesticated camels originated from wild populations – now extinct – on the Southeast coast of the Arabian Peninsula, which tallies with previous archaeological findings.
Than wild animals favoured habitats we don’t now associate with camels such as mangroves. It was also “a rather small geographic region compared with the native distributions of the wild ancestors of other domesticates”, the study notes.
The wild dromedary was already on the way to becoming extinct when domestication occurred – probably due to their restricted geographic range. These wild strains died out by about 2,000 years ago but it was during the 1,000 years of overlap, when the domestic breeds were restocked with wild camels, that their genetic variation was secured.