This post first appeared on February 13, 2012
Like I mentioned in the previous post, I became an avid collector of any examples of splash I could find. One of the most interesting “finds” I made was this particular foal, April’s Spumoni.
She appeared in the American Tarpan Studbook. I should caveat the title with the statement that while these horses were called “Tarpans” at the time, in actual fact they were not exactly Tarpans. Authentic Tarpans have been extinct since the last one died in a Russian zoo in 1909. Here is the last known photo of a living Tarpan, taken in 1884.
The Tarpans in the book are more accurately called Heck Horses. They are so named for the German biologists, Heinz and Lutz Heck, famous for their theory that extinct animals could be recreated by back breeding. That is, they felt that the genetic material that remained in domestic descendants of the original horses could be concentrated through selective breeding, until something approaching a true Tarpan was obtained. In addition to the Tarpans, they attempted to recreate the extinct Auroch.
The work of the Heck brothers is very controversial. The projects, which were conducted at the Tierpark Hellabrunnin in Munich, are often said to have been Nazi-funded. But perhaps more importantly from a genetic standpoint, there are problems that extend beyond the initial premise, which was itself controversial from the start. Questions remain about just how accurate their understanding of the animals they were trying to recreate was. (To be fair, the existing information they had to work with was itself questionable. The Tarpan pictured above, for instance, is thought by some to be of questionable origin.) It is also said that their research was not transparent; the details of what crosses were used were not preserved. Lacking modern molecular tools, they were also limited to what they read in historical accounts, and what they could see in the (alleged) domestic descendants.
Those are a whole lot of qualifiers to say that the little filly at the top was not really a true Tarpan and may not have actually had any Tarpan blood in her makeup. It would be a mistake to say that she is proof that splashed white originated among the Tarpans and made its way from there to domestic animals. Not when two of the breeds believed to be utilized by the Heck brothers were the Icelandic and the Gotland, both of which have modern individuals that have tested positive for the SW1 mutation.
But her situation does have something potentially interesting to tell us about splashed white.
I was surprised to find a splash in that stud book, to say the least. Her minimally-marked parents were even more puzzling. At the time I obtained my copy of the studbook, most of the splashed white horses I had found were from American breeds (Paints, Saddlebreds) or Welsh Ponies. I had not even begun to suspect that the pattern was incompletely dominant, and I had not yet encountered Gotlands Ponies and the way the patterned appeared among them. (I had seen and handful of Icelandic individuals, but was not able to track their backgrounds.) April’s Spumoni was a puzzle, because her parents were so minimally marked. They were both marked with white, which was why they both appeared in the Appendix of the studbook. Her sire had one white coronary band and a small snip. Her dam had a tiny star and a small snip. If Gambling Man has parents that left me scratching my head because I couldn’t figure out which was the culprit, Spumoni was puzzling because I could not imagine how either could be the culprit. They had “ordinary” markings.
That was close to 20 years ago, when I still imagined that there were “ordinary” markings. Markings that did not mean anything. Needless to say, I gave that idea up some time ago. Markings, and what they mean, is the question that drives most of my personal research these days. Back when I first encountered Spumoni, I wondered whether something was tamping down the pattern on her parents, or whether something was amping up the white on her. Initially I overlooked the possibility that it could very well be both, and that the range of patterns out there were being subtly altered by all kinds of boosters and suppressors.
Which is why I think Spumoni is all the more interesting in light of some of the most recent tests. I had noted in the past that some of the seemingly homozygous splash horses (what we would now assume to be SW1/SW1) had parents with almost no white. As more horses turn up with really conservative parents, it is interesting to ask just how minimal a heterozygous SW horse can be when no white boosters are present. It is certainly true that some of the Gotland parents are quite minimal. What was true about Spumoni is that she came from horses solid enough to pass for the regular register, which required that horses be unmarked. Her parents were marked, of course, and that placed them in the Appendix. All four of her grandparents, though, were registered as unmarked. In the cases where photos are available, the individuals look truly solid. Spumoni also had a full sister that had white feet, and her sire had a full sibling with a blaze and socks. All these horses trace back to unmarked horses. It is possible, of course, that the zoos involved misidentified the horses when compiling the studbook. (The early horses were all the property of zoos.) Still, it was a small breeding community, with a small group of founder animals, so it seems unlikely that several of the more influential founders were falsely described as unmarked.
As more horses are tested, we may find out just what those outer limits are. The idea that we may start getting clues about what causes markings on horses is very exciting. That is the big puzzle, after all.