Researchers Study European Sport Horses' Paternal Lines

Researchers Study European Sport Horses' Paternal Lines

Polymorphic research--which investigates multiple genes on the Y chromosome (which is only present in males)--has led researchers to conclude that today’s European sport horse can be categorized into six major lines.


Horse breeding is becoming more high-tech: By studying multiple parts of the Y chromosome in stallions, Austrian researchers are mapping out picturesque paternity lines that reveal how the modern sport horse came to be.

This “polymorphic” research—which investigates multiple genes on the Y chromosome (which is only present in males)—has led researchers to conclude that today’s European sport horse can be categorized into six major lines, said Barbara Wallner, PhD, of the Institute of Animal Breeding and Genetics at the University of Veterinary Medicine in Vienna.

These lines are represented by what scientists call “haplotypes,” which are DNA classifications based on close similarities of certain genome segments. These classifications indicate a major genetic difference from other haplotypes, suggesting different lines of breeding. In a 2011 study German researchers determined that modern horses had very little variation in the Y chromosome when compared to wild horses; Wallner’s group is focusing on what kinds of variations exist in the modern horse.

In today’s domestic European horse, the fact that there are only six haplotypes in the male lines is significant and represents very selective breeding, Wallner said. However, this isn't cause for concern, as maternal lines still vary significantly. Last year, a group of Italian scientists found 18 haplotypes in modern horses worldwide based on maternal genes.

One of the Y chromosome haplotypes, which the scientists are calling “HT1,” seems to be the oldest and most common, Wallner said. The other five appear to have derived from HT1 when genes spontaneously mutated or converted, perhaps after domestication. All six of the haplotypes varied significantly from the two haplotypes previously identified in Przewalksi horses, she added.

One of these mutations (which led to haplotype “HT3”) began with the 18th-century undefeated English Thoroughbred racehorse and breeding stallion Eclipse, Wallner said. That mutation occurred in either Eclipse or one of his sons or grandsons. The HT3 line became very popular, as is reflected in breeding patterns, and is now one of the most common haplotypes among European sport horses, she said.

This genetic research complements pedigrees by giving a scientific aspect to breeding, according to Wallner. “Our data perfectly correlate to what is seen in the pedigrees,” she said.

Adding science to breeding is a step forward toward more refined breeding that focuses on genetic transfer. “With our ongoing sequencing projects, it should become possible to clearly differentiate individual paternal lines,” Wallner said. “This would provide a useful tool for paternity testing and the itemization of deep pedigrees.”

Wallner’s work focused primarily on European sport horses; she said she would anticipate other haplotypes if she had included more horses from other countries, in particular wild horses and mustangs.

About the Author

Christa Lesté-Lasserre, MA

Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor's in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.

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