Feeds:
Posts
Comments

Posts Tagged ‘dog genetic diversity’

Jock Richardson sought virtual immortality by breeding from Wiston Cap so many times.

In an insightful post at the Border Wars blog, Christopher Landauer discusses an important aspect of the dog culture. It does not matter what the aspect of the dog culture it is, but this aspect seems to be the main force that drives people into doing things that are a bit risky for the long-term viability of whatever strain is being produced:

Each hobbyist seeks immortality through the dogs he or she produces, and each hobbyist would like a little notoriety within the designated community.

These two forces are quite destructive. Take the culture of trial border collies, which celebrates Wiston Cap, even if over-using him as a stud had definite health and genetic diversity consequences:

Jock Richardson didn’t have a crisis of conscience after he cashed the 10th check for studding out Wiston Cap and he didn’t quit after the 100th check. He cashed over 388 such checks and Wiston Cap sired over 1,900 registered puppies. I assume that the only thing that stopped Wiston Cap from impregnating as many bitches as possible year round until his death was probably a venereal disease that made him sterile. At some point nature says ENOUGH long before human-kind figures this out. His progeny stopped abruptly several years before his death.

Wiston Cap wasn’t in the dark ages, he lived in the 1970s and his owner died only 10 years ago. Would we praise a repeat performance today or would we condemn it?

No one owns “the breed” and altruism doesn’t exist, so individual ego, self aggrandizement, and desire for immortality through fame trumps the greater good. People whose greatest accomplishment in life is in their dogs do exist and asking them to take their last bow before they have to be dragged kicking and screaming, or in most cases whimpering, from the spotlight, is unseemly. We don’t criticize these people, we put their dogs on our logos and name awards after them. We give them glowing obituaries and make sure that any mention of the breed includes at least one or two homages to their dog. Everyone seems to know that Wiston Cap carried the gene for a red coat color, but no one seems to know that he also carried CEA.

The culture at large rewards this sort of thinking. In the AKC, top producing studs are lauded, as if  a few studs producing as many offspring as possible is somehow good for the population genetics of these breeds.

The problem with dogs is deep within the systems in which these culture exist. They reward competitive values over good sense, and people live in a fantasy world in which the best way to win is to breed from the dogs who do win.  It is almost Lysenkoist to believe that one can breed show dogs or working dogs by breeding from an elite set of studs. Different genes interact with those of different dams, and those things that make those studs so special may not be expressed when bred with a particular dam.

And never mind the parts of the dog that are not inherited but have to be learned through careful training or developed through good nutrition and conditioning.

But even having a good Darwinian understanding of dogs doesn’t stop this very destructive part of the culture.

Dog culture simply is not collaborative enough to encourage the preservation of genetic diversity, and within every culture, there are always people who have nothing to do but pull out daggers against someone who does something they don’t like.

I’m sure they are in every part of society, but in dogs, it seems that it’s those people who wind up having the power, the ones who use bromides and harassment to keep things going their way, and the ones who stand in the way of reform.

Not all people in dogs are like this, and even within the leadership of various clubs, there are people who understand these problems and want to correct them.

To correct them, however, would cause a great shift in what people do in dogs. Landauer explains what this change in breeding ethics would have to look like:

It requires a breeding ethic in which you don’t only select just one offspring from a parent to carry on the legacy. This isn’t hard for males, but few females have more than one significant offspring. Popular sires have no problem creating multiple distributed copies of themselves in the gene pool, but it’s a rare female who has 10 registered children who all have sustained lines.

We don’t have to breed 10 puppies from each litter though, as long as we have breed a diversity of puppies in the past. If a sire and dam both came from litters where just a few of their brothers and sisters were bred, the genetic diversity from the grandparent dogs will be preserved in those cousin lines and the need to preserve those genes in this litter is greatly diminished.

This is why preserving genetic diversity is a community endeavor. No single breeder can accomplish this. No line of dogs can be a universal outcross. No one litter can by itself can capture enough of the genome.

But in most so many strains, breeders select only a handful of puppies as breeders. A few even sell the majority of their stock already spayed and neutered.

This, of course, allows the individual breeder to have a lot more power over his or her strain. It is good for virtual immortality.

It is terrible for genetic diversity, and if we actually wanted to work toward more genetically diverse dogs, breeders would do much more to encourage their puppy buyers to get into this.

And to allow those buyers a bit of freedom to be experimental with their breeding choice.

But that means that the breeder of the original dogs have to let go a bit, and that means less of a chance at virtual immortality within the designated dog culture.

Of course, one could get virtual immortality by encouraging people to increase genetic diversity within a chosen breed and help the long-term viability of the breed and of the species at large.

However, those virtues simply aren’t rewarded within the dog cultures.

But it’s high time they were.

If people actually understood the  looming crisis with MHC/DLA genes in domestic dogs, I don’t see how anyone could think that the current way of doing things is fine.

But then again, I’m an outsider.

Within the fancy and the trial cultures, denialism is the most important thing. Various biologists and geneticists who become part of these clubs seem to forget much of what they learned in school or what they say must be done to save various endangered species.

No one seems to understand that contrived genetic bottlenecks are no better than natural ones.

The former are superior because they are the ticket to fame and immortality within a cultural construct, and the latter are bad because they will kill endangered species.

But they are both bad.

It’s just that the former get reinforced within the human culture that we think they are good.

To solve these problems, we are either going to have to change the culture or start our own competing culture. The public seems to be receptive to changing things. People are skeptical about the various cultures already. We just have to provide something else– something more collaborative and science-based.

Read Full Post »

 

This cheetah and her kitten were shot in southwestern Iraq in 1925. The hunter is a Bedouin of the Shammar tribe, which once ruled a huge portion of Arabia and a smaller portion of Iraq.

 

When I was in seventh grade, I read Sir Arthur Conan Doyle’s “The Adventures of the Speckled Band.” It is a Sherlock Holmes story in which the murderer is a nobleman who keeps all sorts of exotic animals. The actual murder weapon– “the speckled band”– is an exotic swamp adder.

The murderer also kept a baboon and an Indian cheetah on his property.

My seventh grade mind couldn’t handle the Indian cheetah’s existence.

I knew that Cheetahs were African. How could there be Asian cheetahs?

I guess I never looked into at the time. I just assumed that I was right.

The nI began seeing depictions of Indian nobles stroking hunting cheetahs as if they were their favorite greyhounds that they were just about to slip loose after some deer or antelope.

Probably imports from Africa, I thought.

Too bad I didn’t see this film:

Source.

So cheetahs were native to India. The British colonialists used to call the ones used to hunt blackbuck “hunting leopards.”

(Of course, cheetahs are not closely related to leopards. Their closest living relatives are the jaguarundi and the cougar.  The extinct American cheetahs were actually more closely related to the cougar and jaguarundi. The modern cheetah evolved from a cougar-like ancestor that migrated the Old World. It did not derive from the American cheetahs.)

But I did not think much of the Indian cheetahs until I heard of another cheetah population.

Remnant population of Asiatic cheetahs still exists.

And of all places, it is found in Iran. A few individuals have popped up in neighboring Pakistan and Afghanistan, but the bulk of the tiny Iranian population of 60 to 100 is f0und in that Islamic republic.

When I heard that I began to wonder about how extensively the cheetah ranged into Asia.

Quite extensively it turns out. They were once found from the Sinai to Burma (Myanmar). They were found throughout the Indian subcontinent and Arabia and were also found as far north as the Caspian into territory that is now part of the Russian Federation.

But they have now been reduced to a tiny remnant population in Iran.

Asia was once home to a healthy cheetah population.

And it essentially doesn’t exist anymore.

It is quite a shame, because cheetahs, in case you haven’t noticed, are in a lot of trouble.

Cheetahs have a lot going against them, besides losing almost all of their Asian range.

They are not the best fighters in the cat family. They simply aren’t built for it. Their claws are only partially retractable.

And after they run down their prey, it takes them a very long time to get cooled down before they can eat.

They are poorly adapted to defend themselves from depredations from spotted hyenas and lions.

Habitat fragmentation and even legal and illegal hunting to protect livestock from cheetahs have really taken their toll on the species.

But all of these problems are made infinitely worse by another major issue– one that is more in keeping with our discussions on the blog.

Cheetahs– bot Asiatic and African– have a severe genetic bottleneck.

One of the most amazing testaments to this compromised genetic diversity is that cheetahs don’t reject skin grafts from other cheetahs. They don’t have to be relatives.

Some time during Pleistocene, cheetahs almost went extinct.

Their numbers were severely reduced, and they bred back from a very small founder population.

Cheetahs themselves tend to be healthy, for there has been a rigorous selection in nature against deformity and disease.

However, that does not mean that cheetahs are not suffering from some effects of an inbreeding depression.

Male cheetahs have fertility issues. They have low motility in their sperm and generally have low sperm counts.

The Asiatic cheetah in Iran is probably doomed simply because of that problem. And if we have nuclear war between Israel and Iran, well, they are really doomed!

Cheetahs cannot have new genes added to their population.

There are those in the dog world who would point to the cheetah as a success story for a compromised genetic diversity.

I wish they would have picked a better example.

Because cheetahs are a mess.

I don’t know if they can be saved in the long term.

It is really a major crisis in that species.

New genes can’t be added to cheetahs. They can’t be bred to related species. I would laugh if someone suggested that we breed them to cougars for this purpose.

It is simply not a practical consideration.

But with dogs we have so many more options.

Options we are not using for no reason other than we have a bunch of cultural hang-ups that prevent us from considering genetic diversity.

It is a great shame that we are allowing these cultural hang-ups to prevent any careful considerations here.

I’m sure those cheetah conservationists are envious of our situation.

They would like to have new sources of genes, but they don’t have them.

But it should also be a warning, we think we can breed our dogs in this fashion forever, but it won’t be long before they start to be like cheetahs.

And that would be a major tragedy.

Read Full Post »

Virtually all working border collies used in trials are descended from this dog, "Wiston Cap."

Virtually all working border collies used in trials are descended from this dog, "Wiston Cap."

The Canine Diversity Project is a site worth visiting.

How do we create genetic diversity?

We do it by introducing new bloodlines in a population.

Why do we need to do this?

Because diversity gives a population some room. It prevents genetic diseases from become so heavily concentrated in the population. Further, if a  deadly new pathogen suddenly began to spread through the population, some of those individuals in that genetically diverse population might be resistant to it. The chance that this might happen is one reason why so many people are concerned about the genetic diversity of farm animals.

Zoos and breeding programs that produce endangered animals are always worried about genetic diversity. Inbred populations might have lower reproductive rates, as is the case with the cheetah, and the chance of a deadly pathogen killing off whole species is a major concern.

Until recently, dog people haven’t thought much about it.  Genetic diversity in most purebred dogs has been reduced through the advent of organized competitions and an institutionalized fancy. Further, most registries use closed studbooks that only allow new dogs to enter the breeding population for a short time. After this time is past, it is very difficult to add new bloodlines, although they can be imported from similarly closed registries.

Dog shows are often blamed for the problem. Dog shows make certain male dogs rather famous. Male dogs can produce far more offspring than bitches can, and what often happens is that winning studs are used many times. This use of winning studs within a population reduces genetic diversity, simply because so many dogs have the same sire. Over time, the number of dogs with the same sire in their pedigree increases, and because these dogs are more likely to be winners, they are bred together. This problem can happen without deliberately inbreeding. If a great many dogs have the same sire,  at some point, the progeny of these dogs wind up being bred together. If that sire was carrying a bad genetic disorder, you have increased the chance of large numbers of that particular dog population developing the disorder.

This problem is not confined to show dogs. In border collies, the popularity of sheepdog trials has had a similar effect. Virtually all working border collies today descend from a single sire, Wiston Cap. Border collies don’t have problems with an exaggerated body type, but they all pretty much have the same genetic disorders.

Although it is true that some species have survived great reductions in genetic diversity, such as the Northern Elephant Seal, which are all descended from a single male ancestor, it is not likely that dogs are going to be able to survive these severe reductions in genetic diversity. The wolves of Isle Royale (a long observed population) became severely inbred, and their population was unable to rebound for several years after the moose population dropped. Inbreeding is often suggested as one of the reasons for their inability to rebound once moose began to appear in higher numbers.

We need to really pay attention to genetic diversity in our dogs. It is as important as working conformation and temperament in ensuring the long-term viability of our beloved animals.

Read Full Post »

%d bloggers like this: