November 14th
Dog breeders have cost me $4000 so far, and I have never purchased a dog from any breeder. How can this be so? The answer lies in the long-term consequences of dog breeding.
Genetics is immensely complicated; only rarely can you clearly assign any particular gene to any particular trait. Most traits are the result of the interaction of many genes, and many genes express themselves in multiple traits. This is advantageous to life: a species has a robust genome pool that is somewhat resistant to minor genetic defects, yet remains flexible enough to adapt to changes in the environment. Few outside the genetics community know the Mendel’s famous experimental results were in fact dependent upon an extraordinary stroke of luck: each of the traits that he tracked was isolated to a single chromosome, and so his simple experiments yielded simple results. Had he tracked other traits, he would have produced an undecipherable tangle of results.
The breeding of domesticated plants and animals has been a slow and jerky process. Humanity has bred a huge range of flora and fauna to meet its needs: horses, corn, wheat, cattle, yams, pigs -- it’s a long and impressive list. Most of these breeds are healthy and robust. Few people realize just how much trial and error has been involved in this process. The development of any single breed has taken centuries and involved thousands to millions of trials. Many of those trials have produced wretched results; only occasionally have human efforts yielded progress. But over the millennia, the accumulation of these tiny steps has added up to major results.
Consider, for example, the domestication of teosinte in Central America. This is a grass with a skinny head containing about a dozen hard kernels of seed. Starting 9,000 years ago, farmers in Central America began growing and steadily improving teosinte; the result is maize:
Modern agronomists have determined that only five genes separate modern maize from teosinte, yet the development of the huge ears we now eat took thousands of years. That’s because each of those five genes was mixed with lots of other genes, so that developing breeds that isolated their changes to just those five genes took a long, long time. Remember, too, that maize is an annual: people were able to grow thousands of plants every year and select the best for planting the next year. This made the breeding of maize a fairly rapid process.
My point is that the progress we have made with maize is derived from literally billions of genetic experiments, involving millions of farmers evaluating billions of plants over thousands of years. Nowadays, the genetic development of maize continues at agricultural research centers all over the world, and such research efforts involve planting entire fields with thousands of plants.
Breeding animals is a slower process, because most domesticated animals require longer for each generation (two or three years at the minimum) and because we can’t raise the numbers of animals that we do when breeding plants. Nevertheless, considerable progress has been made in the breeding of domesticated animals, the dog being the best example. Dogs are descended from wolves, and the difference between a wolf and, say, a chihuahua is striking. Again, this process has been going on for thousands of years; some scientists think that the domestication of the dog began as early as 100,000 years ago. Let’s do a quick estimate of the number of breeding trials that have been carried out since, say, 10,000 years ago, when there were at most 10 million people. Let’s assume one dog per person, with one generation every two years, and a linear growth in population up until 1700 CE, when there were about a billion people. I therefore estimate that there have been about a billion dogs over the course of human history. That’s one billion genetic trials to achieve the great variety of dogs that we had in 1700 CE. My point here is that it takes a LOT of trials to achieve robust, healthy breeding of a species.
Now let’s turn our attention to modern dog breeders. The typical breeder maintains a stock of at most a few dozen animals; that in itself renders any breeding experiments carried out by dog breeders risibly inadequate. You simply cannot carry out any kind of rational genetic selection on such a tiny population. Indeed, geneticists believe that you need at least 500 individuals of any given species to maintain its genetic health; a smaller gene pool simply doesn’t have the breadth required to maintain a healthy population. And yet breeders work with a few dozen animals -- an absurdly low base with which to work.
It is true that breeders swap animals, creating a larger gene pool for a breed; this much improves a bad situation. Moreover, the best breeders pool information about their animals, providing better feedback for the selection process. An ideal example of this process is demonstrated in this description of a project in the late 70s to reduce the incidence of a flaw in uric acid metabolism in Dalmatians, due to a genetic association between one gene affecting spot production on the coat, and another gene affecting the metabolism of uric acid. This admirable project resulted in dalmatians that do not possess the genetic defect while retaining their spots. Unfortunately, this genetic improvement has not spread through the dalmatian population; thirty years later, many dalmatians still suffer from bladder stones and other health problems due to this genetic defect.
Indeed, dogs these days suffer from a huge range of genetic diseases; these diseases are so common that there are lists of health problems that dogs are subject to, and even lists of health problems that particular breeds are subject to. Americans spend about $6 billion per year on veterinary care for their dogs; a significant portion of that expenditure is due to treatment of genetic defects in dogs. This is where my own expenses enter the discussion. I have spent $4,000 on surgery for dogs with torn cruciate ligaments in their rear legs. These weak cruciate ligaments are a direct result of poor breeding practice.
One reason for so many health problems in our dogs is that breeders seldom keep track of their dogs once they leave the breeder’s care. They can verify the appearance of the dog, but genetic flaws often fail to manifest themselves for years. When that happens, it’s the owner, not the breeder, who learns of the problem and pays for it.
It’s true that the serious breeders take great care in controlling the genetics of their animals. The American Kennel Club goes to great lengths to insure the genetic health of its breeds. Nevertheless, as you can see from their Dalmation breed standard, they worry a great deal more about the physical appearance of the animal than its underlying genetic health. In something like a thousand words of text specifying the traits required of a Dalmation, there is nothing directly addressing genetic health.
The biggest problem, of course, comes from the puppy farms and amateur breeders who don’t know genes from jeans. These people spit out millions of defective animals, contaminating the canine gene pool in the process. Obviously, we need to address these people first.
What needs to be done The most obvious step we should take is the legal prohibition of breeding animals for sale without an appropriate license. We have learned the hard way that lots of services (law, medicine, hairdressing, home construction, teaching, for example), need licenses or certificates to keep the charlatans away. Yet no such requirement exists for breeding animals, even though “buyer beware” is inadequate to protect somebody seeking a new pet. I get all my animals from the pound, and there is of course no way of knowing whether any animal there is likely to have genetic health problems. That’s the problem: the charlatan breeders have contaminated the overall gene pool for dogs so badly that it’s almost impossible to find a genetically healthy animal. I am victimized by people whom I could never hope to identify -- and I want to protection from such people.
The solution, then, is to make it unlawful to sell a dog or cat without possessing a valid breeder’s license restricted to a particular breed. This would dramatically improve the gene pool of our dogs by removing the source of genetic contamination. Yes, home breeding would continue, but natural selection works, to some degree, on animals bred by accident. At the very least, such home-bred animals are not subject to unnatural selection, which usually makes matters worse.
I would also like to see every single animal that is sold by a breeder to be injected with a subcutaneous identification chip, which can in turn be readily used to look up the genetic heritage of the animal on the Internet. This would permit breeders to learn about the long-term health of their animals. Indeed, after breeders have had time to adjust to this new system, I would like a law that assigns the cost of specified genetic health problems to the breeder rather than the owner. If breeders had to pay for their mistakes, they’d be more careful in their efforts.
Such measures, I think, will save us billions of dollars each year in veterinary costs for our animals. I realize that all breeders will resent such an intrusion into their efforts -- but there are a lot more people, people like me, who suffer from their mistakes. Given the high costs of those mistakes, such intrusion is justified.