Peter Green MRCVS examines the latest breakthroughs in equine genetics.
Equine genomics have moved on swiftly since the first description of the complete horse genome (the equine “library” of genetic material) in 2009.
Geneticists and evolutionary biologists have been waiting impatiently to see if up-to-date genetic techniques can shed any light upon the origin of the domesticated horse, which has been hotly debated for years.
It is now thought that the knowledge of how to domesticate a wild horse spread across the globe from western Asia at the same rate as the recently-domesticated horses themselves were moved and traded. But this seems only to apply to mares.
Studies suggest that the patrilines, or male genetic input, to domestic horse stock came from very few wild stallions indeed and that almost all modern domestic horses have arisen from a tiny number of wild sires. So while extra wild mares were most probably incorporated into domesticated herds as the herds moved out of western Asia, no more wild stallions were added.
And which ancient horse and pony breeds are directly descended from wild ancestors? None of them — even the world’s oldest breeds, such as the Fjords pictured above, are not directly descended from wild ancestors. All breeds so far genetically analysed have varying amounts of pre-domesticated DNA remaining, yet none is truly representative of the prehistoric wild horse.
This vet news feature was first published in Horse & Hound magazine