Some three years ago the excellent Manchester Guardian printed a fascinating article about thoroughbred genetics. I’ll link it below but there are a couple of points of interest which I’d like to comment on.
Firstly, the writer mentions the estimation that around 30-35% of racetrack performance is determined by genetics. Unfortunately, a detailed analysis of how this figure was arrived at was not produced, but you’d have to think that this is one very interesting statistic. Does it mean that agonising over the best possible mating is a waste of time or does it mean something entirely different. Perhaps it could suggest that since environmental factors affecting racing performance do not vary very much at all (please note, this comment is just for the sake of argument), then it must be the 30-35% genetic factors which make the difference.
The second really surprising aspect of the article was the assertion that inbreeding is much more likely to occur in the pedigrees of good sprinters than of good stayers. This is probably reasonably true and there’s also an implication is perhaps that good sprinters are easier to select from an analysis of their pedigrees than are good stayers. I’m not sure whether this data is solely sourced from the Northern Hemisphere, and it’s fair to say that the terminology used in this section of the article is anything but exact, but my experience has been that this is not the whole story. Sprinters can come from the most surprising bloodlines – Vonusti (Ustinov), Start Wondering (Eighth Wonder) – but stayers are much more predictable. It’s very rare for a 2400 winner to be sired by a sprinting stallion. I must admit that I haven’t any reliable data to back up this theory but it certainly my impression based on looking at thousands of sale catalogues.
Anyway, here’s what The Guardian has to say.
https://www.theguardian.com/science/2014/jun/22/horse-breeding-genetics-thoroughbreds-racing-dna
