Gone are the days when men had to rely on horses for transportation, but the animal certainly played a crucial role in human history.
The domestication of the horse, which occurred about 5,500 years ago, has paved the way for the easier and faster movement of men. It revolutionized civilization, trade and warfare, as well as stimulated agriculture. Now, a new study pins down these crucial equine contributions to 125 genes.
For the study published in the journal Proceedings of the National Academy of Sciences on Dec. 15, evolutionary geneticist Ludovic Orlando from the Natural History Museum of Denmark at the University of Copenhagen, together with colleagues, examined the DNA taken from 29 horse bones excavated in the cold regions of Taymyr Peninsula in Russia. The bones date back to between 16,000 and 43,000, years ago, which was long before the domestication of horses.
By comparing the ancient DNA of the wild horses with those taken from five present-day domesticated horses, the researchers found that some genes that are present in today's breed did not exist in their ancient counterparts, suggesting that these are recent mutations.
The speed gene, for instance, which can be attributed to one of the most notable characteristics of modern-day horses, was found lacking in ancient horses and thus a relatively new mutation.
"Our work demonstrates the power of ancient genomes to reconstruct the complex genetic changes that transformed wild animals into their domesticated forms, and the population context in which this process took place," the researchers wrote.
The researchers particularly identified 125 genes that produced traits ancient breeders could have found very ideal in the horses they chose. One group of genes was associated with cardiac strength, coordination, balance and skeletal muscles, which enabled the horses to pull plows, run fast and be used for chariotry.
Another group of genes found to be more abundant in present-day domesticated horses was involved in cognitive functions, such as fear response, agreeableness, ability to learn and social behavior, and this set of genes could have played a crucial part in the taming of the animals.
"Perhaps even more exciting as it represents the hallmark of animal domestication, we identify genes controlling animal behavior and the response to fear," Orlando said. "These genes could have been the key for turning wild animals into more docile domesticated forms."
Orlando said that the study could help improve the fate of the few wild horses that are in existence today.
