John Ryan
- - Juillet 15, 2025 34
 Consider that the Y Chromosome descendant stallions of the Godolphin Arabian and Byerley Turk Stallions will soon be extinct, leaving just the male line descendants of the Darley Arabian present as sires of future Thoroughbred horses. What is the likely genetic consequences of having just one active Y Chromosome male line being reproduced in the Thoroughbred breed?
Genetic Consequences of Single Y Chromosome Line in Thoroughbreds by John Ryan (Melbourne- Autralia)
Genetic Consequences of Single Y-Chromosome Sire Line in Thoroughbred Horses
Background: Foundation Sire Lines and Paternal Legacy
Thoroughbred racehorses trace their pedigree in direct male line (tail-male) to one of three foundation stallions imported to England in the late 17th and early 18th centuries 1. These founders - the Darley Arabian, Godolphin Arabian, and Byerley Turk - established the original sire lines of the breed. Over time, however, the dominance of the Darley Arabian's lineage (through his famed great-great-grandson