Genetic Diversity & Complex Ancestry in the Arabian Horse by Beth Minnich and Michael Bowling
DNA as a Storyteller The Arabian horse possesses a rich history, intimately connected to the physical environment of its ancestral homeland and culture of Bedouin caretakers who nurtured its development. It is unclear when and where the horse was introduced to the area historically known as ‘Arabia’. Yet, from a regional proto-Arabian that was developed over millennia, the nomadic horse breeding tribes cultivated the foundation of the breed now known as the Arabian horse.
“All of us in trying to understand today and tomorrow look to yesterday; to try to get some glimpse of what came before us and some lessons that can help us meet the future.” Kenneth W. Harl, PhD Professor, Dept of History / Tulane University
From the mapping of the horse genome in 2007, genomic tools were developed that provide access to information offering expanded perspectives for viewing breed ancestry. These new observations provide a gateway to deeper understanding of the Arabian breed, helping to connect the threads of culture, history and genetics. With these threads, we can weave a more detailed tapestry depicting the origins of the Arabian horse, to help guide preservation efforts of this iconic animal. To help tell this story, we turn to a paper entitled ‘Genome Diversity and the Origin of the Arabian Horse’ in the journal Scientific Reports (June 2020). Conducted by an international team of researchers from the USA, Qatar, Iran, Austria, Poland and Hong Kong, the project sought to study genomic diversity in the Arabian horse and its relationship to other breeds, particularly the Thoroughbred racehorse. Led by Dr. Samantha Brooks (University of Florida) and Dr. Doug Antczak (Cornell University), the study used a large number of Arabian horses of diverse origin and bloodlines. Project funding was provided by a grant from the Qatar National Research Fund (a member of the Qatar Foundation) to study the genomes of the Arabian horse, Arabian oryx and Dromedary camel, three species with deep cultural ties to the Middle East. Project support was also received from several additional organizations, including non-financial support from the Arabian Horse Foundation. There are several storylines shared in the paper, so there is a lot to conceptually sort through. Due to space limitations, this article will focus on the genetic diversity component of the project. But for interest, the main summary points across the study include: 1. The Arabian breed has a unique genetic profile marked by broad variation and underlying complex ancestry consistent with an ancient origin: • Globally, Arabian horses display a large degree of genetic diversity, more than many other breeds of horse. • Registered Arabian horses were identified in the Middle East that carried expanded genetic and phenotypic diversity. • Straight Egyptians have a distinct genetic signature and less genetic variation than other Arabian bloodline groups considered. 2. Genomic regions were identified that may be associated with important traits of the Arabian horse, such as head shape and athletic ability. 3. Little overall genetic similarity of Arabians to Thoroughbreds was detected, including lack of evidence for Arabian stallion Y chromosome ancestry. 4. Strong evidence was found for recent interbreeding of Thoroughbreds with Arabians used for flat racing. Before we begin this journey, some background needs to be provided. DNA samples were considered from 378 Arabian horses of diverse 14
