Keep going and you get to https://en.wikipedia.org/wiki/Darley_Arabian ,

> Most Thoroughbreds can be traced back to Darley Arabian. In 95% of modern Thoroughbred racehorses, the Y chromosome can be traced back to this single stallion.

Certainly! But how on Earth did you stumble across that?

Hmm, now I'm curious. If the wikidata project is somewhat up to scratch you should be able to do a SPARQL query on the horse and its ancestors (which is kind of an ideal use case for a graph query language).