Equine-related tangents


My oldest son has been struggling with freshman Biology, so the concept of evolution has been on my mind a lot lately. I have also been reminded that evolution applies, not just to organisms, but of points of view. Sometimes it can be easy to forget that you once held a different view – unless of course you are foolish enough to write it down for others to find later. I have been writing about horse color long enough now that I have had that happen!

The reminder of this came from my husband. Longtime readers of the blog have probably picked up on the fact that I have a strong interest in the issues surrounding genetic diversity. It is, as I have mentioned, one of the themes that runs through the upcoming books. My close friends could probably warn readers that it is a tempting soapbox for me, particularly when it comes to the topic of dogs. That was exactly what I was doing – standing on that soapbox – when my husband reminded me that I once held a very different point of view on the subject.

He has every reason to remember this, since there was a time when the topic came up often between us. My husband is a physicist working in the field of optics. When we first met, he was intrigued by the possibilities of using genetic algorithms to solve complex design problems. A genetic algorithm is a mathmatical tool that narrows down variables by “breeding” the possibilities until an optimal solution is found. He was experimenting with genetic algorthims, and I had recently bought my first Arabian mare after spending most of my teen years planning my future breeding program. I was more than happy to explain all the different inbreeding, linebreeding and outcrossing schemes breeders had developed over the years.

My husband used this diagram to illustrate a chapter on genetic algorithms in his book. My understanding of how he used the idea doesn’t go much deeper!

I was familiar with them because I had my heart set on breeding animals, most specifically Arabian horses and Rough Collies. Since I could not convince my parents of the pressing need to start populating our home with dogs, or to acquire land for horses, I used the time to learn all I could for the day when I could do those things. When the time came, I was determined to be the most informed breeder possible. I devoured issues of Arabian Horse World. It was the 1980s and  the market for Arabians was at its peak, so each issue brought countless images for a horse crazy girl trying to determine just what qualities she would emphasize in her hypothetical breeding program. While other girls were pouring over fashion magazines and beginning to notice boys, I was filling ring binders with notes on bloodlines and affixing sticky notes to the important pages. As you can see, many of them are still there today.

I was smitten by pictures of the stallion *El Shaklan. The more something looked like an imaginary elven horse, the better. I was not an especially practical kid.

Arabians appealed to my artistic sensibilities. My interest in Collies came about in a more personal way. My grandfather was a Collie man, and encouraged me to read Albert Peyson Terhune’s books. Mr. Terhune had lived in the same town, and traveled in many of the same dog circles, as my grandfather’s family had when he was a boy. Like so many, I fell in love with the breed as it was portrayed in Mr. Terhune’s books. When my parents offered to give me my very own dog for my twelfth birthday, getting a Collie seemed a natural choice.

My grandfather’s favorite Collie, Glengay Sandy Boy. The inscription on the back of his photo is the Terhune quote, “a thoroughbred in body and in soul.”

I knew the “proper” way to obtain a quality dog. My parents, however, had different ideas. I wanted the perfect bitch with which to start my grand breeding program. My parents wanted something within their price range and a reasonable driving distance. The result was the dog at the top of this post. She came from a local farmer who raised a few Collies on the side. She wasn’t the potential foundation female I would have liked to have gotten, but she was a dog of my very own. When you are twelve, that counts for a lot.

My grandfather, when he received her photos, was quite critical. She had a pronounced stop, which was not proper. The angles of her face were all wrong, and she carried her tail in something awful close to a curl. But the real deal-breaker was her prick ears. As soon as she left the puppy stage and those ears went up, he ceased to consider her a Collie. Purebred Collies had tipped ears. She was, he insisted, nothing more than a “Whiffle Hound.” She was no relative of his beloved childhood Collie, Sandy.

Looking back, perhaps that reaction planted the seeds of doubt about what was valued in the animal fancies. It was obvious to anyone familiar with the standard that Brandy was a Collie of inferior type. I would have readily admitted as much. She was, however, a wonderful companion for a young girl. I thought she hung the moon, and her over-large, erect ears seemed like such a little thing in comparison to all that was great about her. We competed in obedience for much of her youth and mine, and it was pretty clear which of us did the better job. (Her ears were less of a limiter than my tendency to confuse left and right.)

Pictures of my grandfather with his ‘thoroughbred’ Collie, Sandy, and me with my ‘wiffle hound’, Brandy. Interestingly enough, we are the same age in these photos and adopting quite similar poses as we encouraged our dogs to do tricks for the camera.

But when Brandy passed away at fifteen years of age, I was explaining close linebreeding (the word I used at the time) to my husband. I had absorbed those ideas from the cultures that surrounded Arabians and Collies, and if anything was going to marinate a young animal lover in the twin concepts of “blood purity” and the usefulness of inbreeding, it would be the world of those two breeds.

But something happened along the way. Soon after we married, my husband’s work took us away from our small farm in Alabama, and to city life here in Charlotte.  I had already begun to question the consuming nature of raising dogs and horses, having seen that more closely through the experience of a number of friends. My interest in breeding animals became more academic, and less about laying the foundation for future activities. My mindset shifted from future breeder to a person who would own a series of beloved family companions, and who just happened to be very interested in the topic of genetics and breeding.

It was the academic interest in animal breeding that exposed me to a new way of thinking about breeding programs. My interest in color motivated me to read journal articles. Many of the authors of those articles also wrote about breed conservation and genetic diversity. Over time, the ideas presented in those papers brought about an evolution in my thinking. Like classical evolution, the change was gradual – a shifted position here, and new insight there, until something quite different took the place of what had been before.

Thankfully for me, this process occurred in the peace and isolation of my own research. I could think about the issues involved in a fairly objective, unemotional manner because no one was clamoring for me to reach a specific conclusion. Now many of those issues have become a source of controversy and bitter battles within the animal fancies. This has played out most visibly in the British dog show world, which was rocked three years ago by the documentary Pedigree Dogs Exposed. That program brought genetic diversity out of the realm of academic papers and into the public square. It is pretty safe to say that unemotional is not a feature of the situation!

In this reaction, many have called the focus on genetic diversity a passing fashion. That is not surprising, since fashion has long driven animal fancies. That is a natural frame for viewing motivations behind breeding decisions. I do believe, however, that calling the subject a fashion does a disservice to kind of thought that goes into breeding decisions. The acceptable angles of a Collie head, and the proper carriage of their ears, is a fashion. The acceptable amount of white on the legs and face on a horse are a fashion. The benefits and hazards of an increasingly homozygous population is a much larger issue. The truth is that breeders are dealing with competing concerns, with uniformity and predictibility being the very essence of selective breeding, and with its opposite, heterogenity, being so closely tied to health. That is not fashion: that is about the limits of the system as it really is. It is essential to understand those trade-offs if breeders are to make good decisions.

As I have said, the Equine Tapestry books touch on the subject of genetic diversity. Because the way a registry defines “breed” and “purity” has a huge impact on colors – both what is ruled in and what is ruled out – it is quite relevant. It is also true that misconceptions about purity and breed integrity have big implications for animal coloring. Because color is so easy to see, and is often the result of far more straight-forward inheritance than things like conformation or breed type, it tends to be on the front line of selective pressures. But beyond those issues, it is my hope that the books will raise questions about how we integrate our growing understanding of genetics into real world breeding decisions.

I have a few more posts to make that expand on some of these ideas, since I want to bring some of these ideas back to issues that touch more directly on color. I also plan to add another page (much like the Splashed White Project page) to the blog with a collection of links for further reading on genetic diversity. Perhaps they can plant the seeds for a more rational dialogue on the topic.

Twenty years ago, when I talked to my husband about linebreeding, I never mentioned genetic diversity. It was not a concept that had come up in my reading at that point. Today when I pulled the copy of my husband’s book, thinking I might find some of the images that came from his work in genetic algorithms, I found the following passage:

We intuitively know that larger populations will bring greater diversity and better sample the solution space. If the ranking function is nearly flat, poor attributes will stay in the population longer. If the ranking function is steep, the population swiftly becomes inbred. A lot of mutation can slow the convergence, while no mutation will lead to premature stagnation through inbreeding.

That passage pretty much sums up the situation facing breeders. If the selection process (what he calls a ‘ranking function’) is minimal, we will get a mix of good and bad attributes and not a lot of control over which we get from any particular breeding. That is the part I knew. At the other end, if we use extremely strict selection, we run the risk of a dead end where the variables present are too limited to provide the answer to a problem. For many, my younger self included, that is the missing piece. I may not have understood then, but the math certainly gave my husband a more complete picture. It almost makes me wish I hadn’t spent so much of my high school algebra classes doodling horses in the margins of my notebook.

In a previous post, I included this Currier & Ives print when talking about how nineteenth century horsemen often associated spotting patterns – pinto or appaloosa – with oriental horses. Their role in circuses, accompanied by handlers with fanciful costumes, probably did a lot to set this idea in the minds of many. It wasn’t just the general public, though. The earliest American stud books often contain references to “spotted Arabian” ancestors. Alexander, the horse pictured in the print, was himself entered into the American Stallion Register.

ALEXANDER, spotted, black and white, 15-3/4 hands, 1200 pounds; foaled about 1822. Owned by Page’s circus, who purchased him in the West, and sold him about 1831 for $1000 to a company at Middlebury, Vt. Advertised, 1833, at Middlebury and Vergennes, Vt., by S. H. Baker for the owners. Terms, $7 to $10. In 1836 Harvey Yale of Middlebury bought one half interest in him, and had charge of him two seasons, one of which he was kept at Hancock, Vt., by Mr. Church. Mr. Yale sold him to Mr. Twilight, Vershire, Vt.

Mr. Yale, in an interview, 1885, said: ” Alexander was a large horse with spotted color, and called a Spanish horse. He weighed about 1200 pounds. His true breeding was not known. A company at Middlebury bought him of a circus company at Rutland. Hough made the trade. He was a good-looking horse, very intelligent, and a good roadster, but his stock varied, and took a long time to come to maturity. Some had light manes and tails.”

Sire of dam of Gray Eagle (Earing’s), and 2d dam of Benedict Morrill.

In that entry, he is referred to as a Spanish horse, not an Arabian or other oriental breed as his advertisement might suggest. It may be that the circus later changed his background story, or they may simply have conflated the term Barb with Arabian. Although modern horsemen think of those as being opposites, during the time Alexander was alive the terms were often used interchangeably.

It was situations like this that were behind the original prohibitions against spotting in the American Arabian registry. That organization was a relative late-comer among American stud books, so it had close to a century of misinformation about its breed to overcome. It is pretty clear that the horses the founders had in mind were the tobianos and the leopards like Alexander, and not the sabinos that really were found in the population. Unfortunately overturning the white rule took a long time, because the reaction to the misinformation created its own misunderstanding of the true nature of Arabian coloring. Instead of “Arabians are never spotted like that”, people became convinced that “Arabians are never spotted.”

But for a time, many American breeders thought horses like Alexander showed their blood-horse origins with their coloring. The colors themselves had largely fallen out of favor at that point, but their presence in the back of the pedigree did not raise eyebrows the way it certainly would today. It is not just the American Stallion Register, either. There are “spotted Arabians” listed in the backs of pedigrees in most of the American light horse stud books from that era. Undoubtedly many were pintos, but the fact that some may have been leopards like Alexander leads to an interesting question. Just how many American light breeds carry hidden patterning genes?

The two horses listed as descendants of Alexander, Gray Eagle and Benedict Morrill, also appear in the first volume of the Morgan stud book. Neither was described as spotted, but the leopard pattern gene isn’t visible without the leopard complex (Lp) gene to activate it. Alexander would have had Pattern1, since he was a leopard, and he could have passed it along to his offspring. This is also true for any of his daughters that were used, but not recorded, in the backs of pedigrees, as well as any other leopard patterned horses found during that time. It is pretty clear that almost as soon as the stud book movement got off the ground, odd colors were systematically eliminated among finely bred horses. In the case of some of the appaloosa patterns, though, the component necessary for the louder parents could have remained among those horses that did not get Leopard Complex .

Someday testing may allow breeders to check solid horses for the presence of these hidden genes. If pattern genes are found, they might just come from some of these “spotted Arabians”.