WCM-Q study helps shed light on Arabian horse's genetic heritage
July 18 2020 11:00 PM
Scientists at WCM-Q helped conduct a comprehensive global sampling and analysis of the genomes of 37
Scientists at WCM-Q helped conduct a comprehensive global sampling and analysis of the genomes of 378 individual Arabian horses in 12 countries.

Researchers at Weill Cornell Medicine-Qatar (WCM-Q) have helped probe the genetic diversity and origins of the Arabian horse, prized all over the world for its beauty, grace and athletic endurance.

Renowned for its ability to thrive in extremely hot, arid environments, the Arabian is the oldest recorded breed of horse, with credible documentation stretching back more than 2,000 years placing its development in the Middle East.

Working in collaboration with an international team of fellow researchers, scientists at WCM-Q helped conduct a comprehensive global sampling and analysis of the genomes of 378 individual Arabian horses in Qatar, Iran, Poland, the US, Jordan, Kuwait, the UK, Australia, Denmark, Canada, Egypt and the UAE. Blood and hair samples were collected from the horses over an eight-year period.

The international team of scientists was led by the University of Florida’s Samantha Brooks, a UF/IFAS assistant professor of animal sciences formerly based at Cornell University in Ithaca, New York; Doug Antczak, the Dorothy Havemeyer McConville Professor of Equine Medicine at the Baker Institute for Animal Health of Cornell University; and Andy Clark, the Jacob Gould Schurman Professor in Cornell’s department of molecular biology and genetics.

Researchers at WCM-Q, led by Dr Joel Malek, Associate Professor of Genetic Medicine, used the college’s state-of-the-art equipment and expertise to assist with the sequencing of the horse DNA. The study was made possible by National Priorities Research Programme (NPRP) grant 6-1303-4-023 from the Qatar National Research Fund, a member of Qatar Foundation. The paper, titled ‘Genome Diversity and the Origin of the Arabian Horse’ has now been published in 'Scientific Reports', a journal from the 'Nature' series of publications.

Brooks said: “The Arabian horse has a special mystique due to the long recorded history of the breed. Arabian horse breeders, in particular, know their horse’s bloodlines many generations back. What we found was that in the area where this breed originates – likely the near East region, but we don’t know exactly – there’s a healthy level of diversity. This is particularly evident in populations from Bahrain and Syria, which suggests these are some pretty old populations.”

The horse is prized for characteristics like heat tolerance and endurance, as well as its unique appearance, with a dish-shaped facial profile, wide-set eyes, an arched neck and a high tail carriage. It has been exported from its ancestral homeland for centuries, with some modern lineages drawn strictly from these smaller genetic pools, giving the breed a reputation for inbred disorders. While this was true for some groups they tested, Brooks noted, they also found remarkable diversity when considering the breed as a whole.

Brooks contrasted the discovery of more diverse populations with the samples they received from racing Arabians. Another longstanding myth says that the Arabian contributed genetically to the modern Thoroughbred, but the racing Arabians’ DNA told a different story.

“What we found in these samples was not that much Arabian ancestry was part of the Thoroughbred line, but the opposite: that Thoroughbred DNA exists in most of the modern racing Arabian lines, indicating a more recent interbreeding within this group,” Brooks said. “I can’t speculate on the how or why, but this is clearly the story the DNA is telling us.”

Another implication of this study, Brooks said, is the potential to identify the genetic regions that determine some of the Arabian’s unique traits, like their facial profile. This could be expanded to identify the marker for other horse breeds’ head shapes, for example.

Dr Joel Malek of WCM-Q said: “It was extremely gratifying to be part of this fascinating and interesting research about the iconic Arabian horse, which is so important to this region. We are very proud to have been able to work with so many talented and dedicated researchers all over the world on this project, which underlines WCM-Q's commitment to pursuing projects at the cutting edge of science that have great local significance, in line with the goals set out in Qatar National Vision 2020.

“We are also very grateful for the support this project received from Qatar Foundation through Qatar National Research Fund, which made the research possible.”

The study has a long list of co-authors, with contributors from the University of Tehran, Iran; the University of Kentucky; the University of Agriculture in Kraków, Poland; the Hong Kong Jockey Club; the Equine Veterinary Medical Center at Al Shaqab (a Qatar Foundation member) in Doha, Qatar; and the University of Veterinary Medicine Vienna, Austria. Elissa Cosgrove from the Clark lab and Raheleh Sadeghi, a visiting scientist from Iran in the Antczak lab, shared first co-authorship of the study.

Dr Khaled Machaca, Professor of Physiology and Biophysics and Senior Associate Dean for Research, Innovations and Commercialisation at WCM-Q, said: “It is extremely pleasing that the advanced capabilities in genomic analysis that we have developed in the Biomedical Research Programme at WCM-Q allow us to contribute to ground-breaking international projects such as this one. The Arabian horse is truly a majestic creature and it is wonderful to be able to shed light on its genetic heritage in this way.”

The study can be read in full at: https://www.nature.com/articles/s41598-020-66232-1

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