Genetic history of the ‘ship of the desert’ revealed
A unique and pioneering study of the ancient and modern DNA of the 'ship of the desert' — the single humped camel or dromedary — has shed new light on how its use by human societies has shaped its genetic diversity.
For the first time, an international team of geneticists led by The University of Nottingham, the University of Veterinary Medicine (Vienna) and King Faisal University in Saudi Arabia, have shown how important long-distance and back-and-forth movements in ancient camel caravan routes were in shaping the species' genetic diversity. The research is published in a top scientific journal, Proceedings of the National Academy of Sciences of USA.
Single-humped 'Arabian camels', properly known as 'dromedaries' (Camelus dromedarius), have been fundamental to the development of human societies, providing food and transport in desert countries, for over 3000 years. The dromedary continues to be a vital resource in trade and agriculture in hot, dry areas of the world, providing transport, milk and meat where other species would not survive. In the current context of climate change and advancing desert landscapes, the animal's importance is increasing and there is new interest in the biology and reproduction of the species.
The researchers have collected and analysed genetic information from a sample of 1,083 living dromedaries from 21 countries across the world. The team combined this with an examination of ancient DNA sequences from bone samples from early-domesticated dromedaries from 400-1870AD and wild ones from 5,000-1,000BC to reveal for the first time ever an historic genetic picture of the species.
Professor of Genetics and Conservation, Olivier Hanotte, from the School of Life Sciences at Nottingham, said: "Our analysis of this extensive dataset actually revealed that there is very little defined population structure in modern dromedaries. We believe this is a consequence of cross-continental back and forth movements along historic trading routes. Our results point to extensive gene flow which affects all regions except East Africa where dromedary populations have remained relatively isolated."
Dr Faisal Almathen from the Department of Veterinary Health and Animal Husbandry at King Faisal University in Saudi Arabia, added: "The dromedary has outperformed all other domesticated mammals, including the donkey, in arid environments and continues to provide essential commodities to millions of people living in marginal agro-ecological areas. The genetic diversity we have discovered, thanks to restocking from wild 'ghost' dromedary populations, is quite remarkable in the history of its domestication. It underlines the animal's potential to adapt sustainably to future challenges of expanding desert areas and global climate change."