Genetic Deep Dive with Julie Goodnight & Doc Gunner

EtalonDx founder and CEO, Christa Lafayette, recently sat down with the amazing Julie Goodnight and Dr. Ben Buchanan of Brazos Valley Equine Hospital to record Julie’s latest episode in her podcast series, “Ride On with Julie Goodnight”.

The episode, titled “Doc Gunner: Genetic Deep Dive (Part 1)”, is about the genetic profile test report for Julie’s 4-year-old foster horse, Doc Gunner. Julie and her team had no history on this horse prior to December of his 3-year-old year. In an effort to effectively give him the rehab and training he needs to be successful for the rest of his life, Julie chose to have him DNA tested through Etalon Diagnostics, and sat down with Christa and Dr. Buchanan to discuss the results.

Over the course of the discussion, Julie obtained answers to some medical questions she had, and strategized how to manage this horse going forward. Plus, the three talked about his unique temperament and character, how that relates to his performance potential, and how that is evident in his genes.

Julie opened with a brief description of the horse. She explained that she has fostered him for 4 months of rehabilitation and training. She and her team have experienced some difficulties with this horse, both medical and behavioral.

After a few months, he is now going really well under saddle at the walk, trot, and canter, and Julie hoping to adopt him out. Julie decided to send a sample of his tail hair to Etalon Diagnostics to perform a full genetic testing. “My job as his foster trainer is to give him the rehab and training he needs to be successful for the rest of his life, and so the more answers I have, the easier it is to do my job.” Julie explained.

Julie gave brief introductions for Christa and Dr. Buchanan, highlighting Christa’s previous work with NASA and Dr. Buchanan’s current work as an internal medicine and urgent care veterinarian with Brazos Valley Equine Hospitals’ locations across Texas.

Julie continued, “So, we sent away the tail hairs about a week ago. Christa can you tell us what you’ve done since then and what you’ve discovered?”

Christa answered, “His results are impressive; he’s got a lot going on. Doc Gunner is the perfect example of why you would want to conduct genetic testing on an animal. He is unknown, he has displayed a few mystery problems, and we want to determine where his future is heading. These are the questions where the genetic insight is especially valuable. So, you mailed us a small tail sample with the roots. We extract the DNA and then we run the genetics on the horse and take a look at the sequencing. In the case of Doc Gunner, we ran the DNA analysis on all of the different regions – color, performance, and health, and we found that he has a lot going on. Where would you like to start?”

“There is a lot of information on this report, I think it is interesting that it is written so that a layman can read it and that you give a lot of references to where you can get further explanations. As his trainer, I am interested in his health and temperament, but the deafness is an area of curiosity for me. I have only worked with one other deaf horse, and that horse was a paint horse with a white face. (Doc’s) most distinctive feature is a white head. What did the genetic report reveal about that and how is it related to his deafness?” Julie answered.

Christa continued, “This boy has quite a few markers for white pigmentation, but he has one particularly rare one – he has a variant for Splash White 3. It is a known deletion, meaning there is a chunk missing out of his genome in a region called MITF. That causes depigmentation and affects the melanocytes, which in turn affects his hearing.”

Dr. Buchanan continued on to explain the physiological explanation for why Splash White 3 can cause deafness due to depigmentation.

“Only 2 horses in the hundreds of thousands of horses that I have worked with were fully deaf, which is easier to prove than partial deafness. A truly deaf horse is an unusual finding.” He emphasized.

The three continued on to sort through Doc Gunners’ various genetic results. Julie stressed that the most important aspects of the report were his results for various health and disease risks, where Doc Gunner had a few notable genes. He carries a copy of both HERDA (Hereditary equine regional dermal asthenia), and HYPP (Equine Hyperkalemic Periodic Paralysis Disease). Dr. Buchanan helped Julie better understand both diseases and how they can affect Doc Gunner’s life as a carrier.

After talking through all of his health results, the team continued on to discuss Doc Gunner’s trait genetics.

“This is where it gets fun!” Christa said. “We test for a number of genes we like to classify as “novel” that aren’t typically available on the commercial market today.”

They discussed his results traits including Lordosis (swayback), Curiosity vs. Vigilance, and Myostatin or the “speed” gene.

Based on Doc Gunner’s results for the “Curiosity vs. Vigilance” gene, which turned out to be two “Curiosity” variants, Christa was able to make a guess on some of his personality traits.

“I am going to guess that he likes to stick his nose in things, he is interested in what you’re doing, and is the first horse to come and see you from across the pasture.”

“You nailed it on the head with Doc Gunner – he immediately approaches whether it’s someone he knows, or a stranger. I like to say that he considers us humans his butlers. He is super willing, curious, and has been easy to train.” Julie affirmed.

“That’s it! Horses with “Vigilant” genes are a lot less social and will be described as aloof, or sometimes even aggressive.” Christa replied.

This team of experts continued on to discuss Doc Gunner’s genetic results in several other areas and gave Julie suggestions on how to move forward with this knowledge and adjust his training and rehabilitation routine. This thrilling conversation is available to listen to on Julie’s website, at JulieGoodnight.com/Podcast. Don’t miss this – and make sure to let us know what you think! What was the most exciting thing they discussed?

Keep an eye out for Part 2, coming soon! The three experts will dive into Doc Gunner’s Ancestry and % Blood analysis, and will dive into possible future testing for sarcoid markers, and if his DNA indicated if Doc Gunner is predisposed to sarcoid tumors.

Listen to the podcast at https://juliegoodnight.podbean.com!