Let’s dive into Olympic half-brothers’ DNA! Tsetserleg vs. Vandiver Genetic Deep Dive

Vandiver and Tsetserleg are two half-brothers that have just competed in this years’ Olympic Games Tokyo 2020 for Team USA Eventing. Both brothers were sired by eventing & Olympic royalty - Windfall II. Accumulating 1,281.5 points over his eventing career, Windfall II is third on the list of United States Eventing Association, Inc. (USEA)'s historical high point standings.

The journey of Vandiver and Tsetserleg to the Olympic level raises questions for curious minds: Is success really shaped by our genes? What can we learn from both of these brothers’ genetic results? How are they alike and how are they different, genetically-speaking?

Let’s take a look at their EtalonDx Equine DNA test results. The MiniPanel PLUS offers information on your horse’s health and disease risk, coat colors and patterns, and performance genetics, all with just a simple hair sample.

First, let’s review their MiniPanel PLUS diagnostic results and focus on their performance genetics results! There are three main traits we are diving into: DMRT3 (“gait”), Temperament, and Myostatin (or speed).

Both horses came back with similar results for DMRT3 and Myostatin: both are negative for the DMRT3 mutation, and both came back as “Endurance” type for Myostatin. The Myostatin variant is associated with racing distance for winning Thoroughbreds, with C/C (Sprint/Sprint) horses excelling at distances of 8 furlongs or less and T/T (Endurance/Endurance) horses excelling in races of 9 furlongs or more. As eventers, they might benefit from having two “Endurance” variants, for the athletic ability and stamina required on the Cross-Country field.

Yet, their results differ significantly on their Temperament (DRD4) test! Vandiver is homozygous for the Vigilance variant, which fits with his description as “not the friendliest horse in the barn”. Tsetserleg, on the other hand, is a barn favorite with a loving personality. Boyd describes him as “cute and cuddly”. “My kids come up to pet the horses, and he’s by far the friendliest,” Boyd Martin said. Not surprisingly, Tsetserleg's Temperament test (DRD4) results came back with two Curiosity Variants!

Now, let’s take a look at their Ancestry & Genetic Composition results:

Doug Payne says that Vandiver’s favorite phase in Eventing is Cross Country, and after analyzing Vandiver’s Ancestry results, the geneticists at Etalon can see why. With 70.89% Thoroughbred ancestry, that might be the key as to why Vandiver makes the perfect Cross-Country mount: quick-footed and athletic. On the other hand, Tseterleg’s % Thoroughbred ancestry is lower than his half-brother, Vandivers’. He does have shared Iberian ancestry (that his brother lacks), and that Iberian blood might be worth noting. Iberian ancestry is also shared by breeds such as Andalusians, Lusitanos, Mangalargas, and PREs - breeds that oftentimes excel in the dressage ring! Tseterleg excels at Dressage, and when Olympic-level fit he does well at Cross-Country, but has difficulty in the show jumping ring according to Boyd. “Show jumping has been his weak phase over the years, and we’ve worked pretty hard at it. It’s very satisfying to get a good round out of him under pressure. I think that Thomas (Tsetserleg) performs better when there’s pressure. I’m not sure if he knows which events are important, but he seems to do really well in dressage, cross-country, and show jumping when we need him.” He might have a competitive edge in the dressage ring thanks to that shared Iberian Ancestry. Let us know what you think!

As a horse owner, understanding your horse’s genetic makeup can help make their lives easier by understanding suitability. Horses may be genetically more suited towards some careers, disciplines, or even people. Your horse’s Ancestry results may help you when it comes to decision-making, increasing the number of tools in your and your horse’s genetic “toolbox” (meaning more genetic variability and the ability to adapt more easily).

We have just seen an example with two related horses, where a simple difference in Thoroughbred and Iberian ancestry may play a huge role in their preferences for different disciplines. While not all of our questions can be answered by genetics alone (environmental factors play a large role in their performance ability), their genetics may give us some insight into their athletic abilities. As our scientists at Etalon Diagnostics gather more information and feedback from our clients, we can also better develop these tools to improve you and your horse’s success, all based on their genetics!