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Posts Tagged ‘genetic diversity’

From the BBC:

Zoo biologists use genetic analysis, demographic statistics and keen familiarity to plan the sex lives of their charges. Their goal is to avoid inbreeding and produce healthy offspring, but sometimes, even the best scientists and most attentive zoo-keepers cannot prevent a tragedy.

The couple seemed like a good pair.

Already sporting a distinguished coat of grey fur at the age of 22, he was a stout, hale and hearty father of a young son.

She was a bit younger – 16 – but those who knew her thought she was ready for motherhood.

And crucially, the computer analysis showed they did not share any recent ancestors, making them a good genetic match.

So, in a Chicago love story, zoo-keepers brought together Kwan, a male silverback western lowland gorilla, and Bana, a demure female. They hit it off, and on 16 November, Bana gave birth to a healthy baby girl.

“Kwan did a really great job,” said Maureen Leahy, curator of primates at the Lincoln Park Zoo in Chicago, in an interview shortly before the birth.

“This romance and match has actually paid off.”

The pairing of Kwan and Bana was the product of a sophisticated breeding plan devised by a team of biologists to ensure the future genetic health of the US gorilla population.

The western lowland gorillas are just one of more than 300 species of animals in zoos across the US whose sex lives are carefully managed by the Population Management Center at the Lincoln Park Zoo.

Species specialists play matchmaker to anteaters, okapis, hyacinth macaws and many others, with more than 80,000 individual critters subject to their plans.

It’s similar to internet dating, said Sarah Long, the centre’s director.

“We use computers and databases to get a male and female together – and sometimes produce offspring,” she said.

“We’re not getting new founders… wild-born animals. Now zoos are more focused on preserving what we have.”

The computer software they use weighs the pedigree of the males and females, in some cases all the way back to the wild, to determine whether they are a good genetic match.

Ideally, they want two animals whose ancestors’ genes are scarce among the population – that is, they have few relatives living in US zoos.

Other factors include the ages of the possible mates and the distance between them, and whether a zoo has the resources to feed and care for another one.

“We’ll look at that giraffe’s age. Is she valuable or not?” Ms Long said.

“Do we want her to breed? Is she the reproductive age? Is there a male out there who she could breed with that’s equally valuable? Is he the right age?”

Last year, Bana was living at a zoo in Brookfield, Illinois, about 20 miles away.

Fifty-two zoos across the country held 342 western lowland gorillas.

But Kwan was sexually and socially mature – and nearby.

The zoo keepers thought Bana would fit into the “sisterhood” of female gorillas already living with Kwan and his six-year-old son Amare.

With the match made, Bana arrived at the Lincoln Park Zoo in a climate-controlled van.

She and Kwan were introduced and a flirtation commenced, with Bana staring longingly at Kwan, throwing him her bedroom eyes for as much as an hour at a time.

“We actually kept her on oral contraceptives to make sure that she was socially established within the group before she got pregnant,” she said.

Even while she was on the pill, she would go into heat and the pair would “solicit each other for breeding”, Ms Leahy said.

Meanwhile, Bana settled into her role as a low-ranking female in the social group. That often meant keeping her distance from Kwan, who as the silverback stood at the top of the social hierarchy.

Eventually, the zoo-keepers decided Bana was ready to be a mum and took her off the pill.

After the infant was born, she thrived and met her milestones for growth, and Bana quickly learned to nurse.

Her social status rose, and she began to eat together with Kwan, who recognised the infant as his own and protected her when other gorillas played nearby.

Even the other juvenile gorillas were curious about the new arrival, Ms Leahy said.

But then, early on the morning of 25 November, zoo-keepers noticed the infant appeared listless in Bana’s arms, and soon after, they realised she had died in the night.

A subsequent investigation shows she perished of a skull fracture, but zoo-keepers are adamant she did not suffer violence.

A necropsy showed no other wounds, no pulled-out hair, no scratches or bruises, and the infant was otherwise completely healthy.

“This was very accidental,” Ms Leahy said.

And Ms Leahy says the infant’s death does nothing to make the population planners think Bana’s match with Kwan was made in error.

“Bana was demonstrating completely appropriate mothering behaviour and the social group itself was demonstrating completely appropriate behaviour [toward] a new infant,” she said, “those were marks of success, in my book.”

For now, the gorillas seem to be in mourning.

“The group as a whole definitely recognised the loss of this infant,” Ms Leahy said.

“There was a lot of gentle nuzzling and touching [from] some of the females that wouldn’t otherwise necessarily interact with Bana. The whole group really attended to her for several days after the infant was gone. Behaviourally, the group was a bit subdued.”

Kwan and Bana have been spending time together, and Ms Leahy hopes the story will have a happy ending.

“We will continue to maintain her breeding recommendation,” she said. In other words: “We’re going to continue to let nature take its course.”

Most of the animals kept in zoos– even those that aren’t endangered in the wild– have issues with genetic diversity.

Even with animals that have proven relatively easy to breed in captivity, pnly certain percentage of wild-caught individuals will breed in captivity.

Being able to breed in captivity is a major selection pressure on zoo animals, and it certainly was a major selection pressure on the animals we domesticated.

To complicate matters even more, many species that are kept in captivity are derived from a very small founding population. There are often just a few lines of different species that are held worldwide.

That means that zoos have to work hard to maintain healthy populations.

As a population, domestic dogs have a lot of genetic diversity, but dog breeders and the institutionalized dog fancy have decided to squander as much of it as possible.

Could you imagine what would happen if zoos got into breeding animals for competition?

It would be a disaster.

You’ll note that zoos work together to maintain genetic diversity.

The dog fancy is far from that collaborative.

Yes, breeders will work together, but the system rewards individual achievement.

One gets rewarded for having the best conformed dog or the one that has produced the most champion.

You don’t get rewards for having the healthiest, most genetically sustainable breeds.

In fact, you wouldn’t be able to get rewarded. It would have to be a collective effort that was sustained over many decades.

That’s so boring.

And you can’t make a game out of it.

 

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Update:  Jess’s post that is discussed here has moved to this address.

It is axiomatic that making analogies from one species to another is often a dubious activity.

We are rightly warned against anthropomorphism when observing animal behavior. We are told to see animals as they are and to do all we can to avoid projecting our human values and cognitive abilities onto other species.

In my hamster-crazed days, I had a hamster escape– as they are wont to do from time to time. One night, I was sitting on the floor watching television, and something crawled up onto my lap. I was bit startled, of course, but when I looked down, I discovered it was my errant hamster.

My 11-year-old mind decided that he came to me because he was bonded to me in the same way dogs were.

I was wrong. Syrian hamsters have no concept of social bonds. The only social bonds they have are between mothers and their nursing offspring. When they are done nursing, she cares for them not one bit.

This particular hamster had associated me with food. I had often fed him from my hands, and he grew quite tame. (He bit me only a few times, which was saying something for those hamsters). He had spent a few days foraging behind the walls, which I’m sure were not well-provisioned. Hunger set in, and because he associated my scent with being fed, he crawled onto my lap.

Now, it is easy to debunk the assumptions I made when I thought my hamster was bonded to me. Comparing hamsters to dogs is folly. It is what children do.

However, when it comes to the science on inbreeding, it is very common for people to make assumptions based upon different species.

It is just as dubious.

Jess Ruffner at DesertWindHounds writes about this issue  in her latest installment that critiques the closed registry system.

One of the things one often sees in defenses of inbreeding and the closed registry system are quotations of studies that involve other species.

However, dogs have a very different natural history from other animals. Other animals have evolved different ways of dealing with genetic diversity issues. Some animals can handle very, very low genetic diversity and low MHC diversity. Others cannot.

The examples that different apologists misuse, misunderstand, or even misrepresent are fairly common. Cheetahs have low genetic diversity and low diversity within their MHC haplotypes, but because they have evolved through this genetic bottleneck and natural selection has been able to work on them, they are able to continue. It is not an ideal situation, but the cheetahs have been able to survive the past 10,000 years with very low levels of genetic diversity. Dogs in closed registry breeds have not evolved within this framework. Natural selection does not affect most Western dogs, which whelp indoors and get regular veterinary care.

Then there is the island fox (Urocyon littoralis) canard. Supposedly, dogs can do fine with reduced genetic diversity because the heavily inbred population of island foxes still has diversity within its MHC. Well, it turns out that those inbred foxes likely exhibited balancing selection. These foxes, like all wild dogs, have very strong inbreeding avoidance behavior, which would have allowed them to choose mates with different MHC genes. Those foxes that were heterozygous in the MHC were better able to survive over those who were homozygous.w And that process would have continued the diversity of the MHC in these foxes, despite being quite inbred. These animals are also not strictly monogamous, even though they do pair bond. That means that litters sometimes have different sires, which means litters can have littermates with very different MHC haplotypes.

(Many domestic dogs have also have inbreeding avoidance behavior. I remember when Cabbage, the long-legged JRT came in season, and Timmy, her four-month-old son, discovered what his equipment was for. Cabbaged savaged him every time he came near. Even when she was receptive to other males, she wouldn’t let Timmy near her.)

Of course, there are animals that have low diversity in the MHC and low genetic diversity all around. Jess mentions the inbred Swedish population of the European beaver, which has very low genetic diversity and very low diversity in the MHC I and MHC II. The beavers are thriving despite being derived from only 80 individuals.  Although  the European beaver population in Russia is not inbred, there are plenty of examples of beavers inbreeding in the wild. Young beavers do not go far from their parents’ territories, and thus, they often breed with relatives. European beavers lack the inbreeding avoidance behavior of wild dogs, and it is not that unusual to see pairs made up of parent and offspring. Because they have evolved with these behaviors, the animals have evolved a very high tolerance for inbreeding.

Inbreeding tolerance is not universal across species. Each species has its own peculiar tolerance for reduced genetic diversity.

Dogs in closed registries do not have the evolutionary heritage that resembles any of these often quoted examples.

Dogs are derived from wolves that have very strong inbreeding avoidance behavior. All cases of inbreeding in wolves have happened when the breeding female has died and one of the female offspring pairs off with her father. Wolves disperse from their natal packs– usually before they are three– and many individuals travel great distances to find their mates and territories. This behavior lowers the likelihood that wolves will mate with a relative.  Wolves evolved as a high genetic diversity species, as the study that found the Goyet Cave dog discovered. Since the Pleistocene, wolves have lost entire MtDNA lineages. it was once a very genetically diverse species.

And as domesticated animals, dogs have also had a gene flow across vast areas.  The camp wolves of the Pleistocene hunter-gatherer bands likely gave up living in territories, so they could easily follow a ready food source. This change meant that camp wolf genes could spread even more than normal wolf genes. Later, when man became pastoralists, there were gene flows from dogs that were following flocks of sheep and goats over vast distances. After all, shepherds always took their flocks into the high mountains during the spring and into the valleys during the winter. Some of their dogs likely ran off and joined local farm and village dog populations, and in this way, domestic dogs retained an unusually high amount of genetic diversity for a domestic animal.

Dogs did not evolve to have closed registries. They evolved to have diverse and dynamic gene pools, and that is why we have so many issues with inbreeding in this species. It has relatively low tolerance for inbreeding.

It was once thought that wolves did fine with low genetic diversity. The wolves of Isle Royale were trumpeted as the best example of a healthy population of wolves that had thrived in spite of a genetic bottleneck that came from being founded by a small founding population that wandered across the ice to colonize the island. However, inbreeding has exposed what is likely a deleterious recessive gene or series of genes that causes bone deformities. The majority of wolves on the island  nowhave these deformities, and they are now having a very hard time killing moose.

But wolves can put up with more inbreeding than dogs can. That is because dogs are a domestic species and are not subject to natural selection. The wolves of Isle Royale might be able to make it if the ones with the deformed backs die off, but if the remaining wolves are all carriers in some way  for that deformity, then it natural selection cannot save them in the way that it did for the cheetah. Because dogs are typically born in houses and well-cared for in the West, dogs with genetic disorders or even weird conformation that prevent them from surviving in the wild are capable of surviving long enough to reproduce.

The natural selection effects on cheetahs cannot happen to domestic dogs– unless you want to risk animal cruelty charges. They can be mimicked by breeding dogs outdoors, but it still doesn’t do much for their MHC diversity.

Finally, some animals are able to survive inbreeding because they evolved within very narrow range that has only so many different pathogens. The pathogens and the organism are able to co-evolve. That why species that have very small ranges don’t need a diversity in MHC genes.

I don’t have to tell you that doesn’t apply to either dogs or wolves. Wolves once had a vast range in Eurasia and North America (perhaps also North Africa). Dogs were domesticated somewhere in Eurasia and then spread throughout the rest of the world. They need diverse MHC genes.

So one must be very careful when reading articles about the viability of inbreeding in domestic dogs– especially when they make comparison to relatively successful wild populations that have experienced a genetic bottleneck. Each species has its own peculiar tolerance for inbreeding that results from its own peculiar evolutionary history and behavior.  Comparing closed registry domestic dogs to cheetahs, island foxes, or beavers is simply not valid.

It is as bad as comparing a friendly domestic dog that comes to you for an ear scratch to an escaped hamsters that comes you for a sunflower seed. The difference in behavior of the two is the result of how these animals have evolved.

And as it is in behavior, so it is for inbreeding tolerance.

Anyone who makes claims otherwise is either misunderstanding the concept or is misrepresenting it.

See also:

MHC, DLA, WTF?

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No problem can be solved from the same level of consciousness that created it.

–Albert Einstein

With the discussion that has happened on this blog, Border Wars, and DesertWindHounds about inbreeding, dog health, and closed registries,. some have asked me what we should do about it.

Yes. The problems with dogs in this regard are mostly systemic, and systemic problems have certain issues associated with them.

One of these is that systemic problems are often hard to observe. If something has been accepted as virtuous for a very long, then it may be difficult for anyone but total outsiders to see anything wrong with them. I am certain that this is the case with most dog issues, because the Western dog fancy has been around for about 150 years. No can remember when the values of the fancy were established, and very few question whether these values are good. If you do, another aspect of systemic problems comes to the fore.

Systemic problems exist because systems have ways of reinforcing themselves. It is more like the indoctrination system of Aldous Huxley’s Brave New World. People are simply conditioned to accept certain negative things as good. The best example of this is blood purity for blood purity’s sake it. It is one religious tenant that cannot be touched. It even supplants reason.

And that’s another problem: reason often doesn’t matter when dealing with systemic problems. The values that maintain the system are very much against those who question. Even harsher measures are used against those who actually do something about the problems they see.

These problems are big. They are almost impossible for the average dog owner to see anyway of combating them.

That’s why so many people get involved in rescue.  Dog rescue does have some inherent problems, but in general, it is nothing quite like the issues surrounding the closed registry problem.

And there is nothing wrong with getting involved in rescue. Each person should participate where one feels most comfortable.

However, the dog owning public can do lots of things to help bring about reform.

One thing should always be understood: The closed registry system is moribund. The AKC has declining registrations year after year. It is on its way out, unless it begins to reform. (Which is unlikely.)

There are other registries, but some of them are nothing more than paper mills. I know of a few that if you breed a jaguar to a dog, I bet they’d register the hybrids. Those registries are not inherently good. They are nothing more than paper mills, and they are part and parcel of the mass production industry. They are not the solution to this problem.

So now that we know that the big institutions that exist to promote the fancy are in trouble, I don’t think we need to waste much more breath criticizing them. Jess does particularly good job at exposing some of the weird belief system that exist within her chosen breeds, and the more those get exposed, the less likely new dog owners are going to pay attention to them.

Logic and reason are your friends in dealing with this mess. Follow this advice from Daria Morgendorffer (I’m dating myself, I know):

Stand firm for what you believe in, until and unless logic and experience prove you wrong. Remember, when the emperor looks naked, the emperor is naked.

Now, use logic and reason when you enter the marketplace in search of a new dog.   Look for breeders who understand issues related to genetic diversity and the long-term health of their breeds or types. You will find that this is a bit harder than using logic and reason, but they do exist. That is because even breeders of working breeds often have a poor understing of population genetics.

That is how the market will sort some of this out.

But the market alone won’t save it. Markets can only work so long as people are informed. My suggestion is that everyone try to get as many people as possible to read the posts Jess and Christopher have put up about inbreeding and closed registries. Those are all very readable. I would also suggest that everyone take a look at The Canine Diversity Project. Some of the links don’t work, but it still a great source for information.

Truth does not set us free. But it is a good first step.

If one has the resources and time, it is probably a good idea for one to consider participating as a breeder. Now, to be a breeder who intentionally produces for genetic diversity is to be really a “man (or woman) in the arena.”  But we need more people breeding dogs. I know that sounds counterintuitive and is against almost all the things we hear from various welfare organizations and breed clubs. However, the only way to increase genetic diversity for the long term health of dogs is to have more dogs breeding– and more people need to be breeders.

Unfortunately, many dog people are simply unaware for the problems that can result from a paucity of genetic diversity. The various cultures do not reward diversity. They reward conformity. They reward top producing sires, and when a male dog excels in some area, everyone wants to breed from him.

If the cultures at large don’t reward diversity, then it is up to consumers to solve the problem. Many people are uncomfortable with this solution, but because the issues with each individual dog population are different and because different breeders have different approaches to solving these problems, we cannot ethically legislate them away.

In the end, all of these problems will be solved. The information continues to flow freely on the internet. People are openly questioning things. The response that these genetic diversity posts have been getting from all three blogs shows that the dog-loving public is deeply concerned.

I don’t think anyone wants to harm dogs, but that which has existed before has been harmful. To think that we can solve these problems without making big systemic changes is a delusion, and it is why I included the Einstein quote at the top of this post. I don’t think we can solve these problems with the current registry systems we have, whether it be the AKC or the ABCA.

And that’s a hard thing to say.

And even harder thing to change.

But people want something better. We just have to work together to find ways of getting there. We have to use what we can to disseminate information and push for reform. If we all keep pushing a little bit, we will get there.

In the past months, I think I can safely say that a large enough percentage of the dog loving public is questioning these issues that we can begin to see things change. People are looking for answers. I don’t have all of them. No one does.

We have to work together to find those answers.

I’m confident that we’ll do it.

 

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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.

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White tigers are heavily inbred. All descend from a single individual, and a lot of them are born with deformities-- like this poor cat.

Christopher Landauer has taken on various myths about the virtues of inbreeding in a series of five posts.

The are pretty good, so check them out.

These are all refutations of some of the memes that are passing in the dog blogosphere.

Dog culture does not reward diversity.

And while we can agree that diversity should exist for diversity’s sake, it does not mean that it should be ignored in our discussions about the long-term viability of Canis lupus familiaris.

It should be noted that a wide variety of animal keepers are much more concerned with genetic diversity than dog people are.

VMS Professional Herpetoculture is a major producer of reptiles for the pet market. It has a very well-written and extensive learning center on its website that includes several lessons in genetics, including a discussion on inbreeding and a discussion on hybridization. These discussions are very applicable to dogs, but unlike dogs, there is no strong cultural sense that one must maintain purity at all costs. Crossbreeding different subspecies and even different species is fun and entirely acceptable in the pet reptile business. The inbreeding discussion even suggests that certain strains and color phases that are produced in captivity might be suffering from an inbreeding depression.

All of it is worth checking out, if for no reason than the attitude of the herp culture is the exact opposite of the dog culture. It is true that everyone wants to breed in the neatest new color mutation, but at the same time, captive reptile gene pools are much more finite. People are concerned that inbreeding could hurt the long term viability of their chosen species.

Of course, we dog people have been spoiled. Our species is relatively genetically diverse, and until persecution pushed them to the far reaches of the northern continents, we always had a chance to bring in “wild blood” from wolves. We can get away with things that would never be tolerated in most species.

However, even other widespread domestic animals are being crossbreed. Cattle breeders have long understood the importance of heterosis. These traits have had a real effect in terms of market price:

When all factors are weighed, the crossbred cow gives you the most benefit. By contrast, the stockman who is merely trying to take advantage of hybrid vigor in the calves (using straightbred cows and bulls of another breed) gains less impact on profitability. Calf weaning weights for crossbred calves are five percent more (and yearling weights four percent more) than straightbred calves. The research study in the 1990’s that came up with these figures showed that a straightbred cow with a crossbred calf earned an average of $23.37 more than if she had a straightbred calf. But a crossbred cow with a crossbred calf netted $116.88 more than a straightbred cow with a straightbred calf. This is one reason a number of producers went to crossbred cow herds.

The market says crossbreed!

Of course, the demand for marbled Angus beef has meant that the market is now demanding animals that are close pure black (Aberdeen) Angus cattle.

But many of those have Hereford crossed in somewhere close in their pedigrees.

It is instructive to read the two links I provided with the literature that Christopher is critiquing.

The attitudes are entirely different.

That’s because dogs have a greater immunity to market forces than beef cattle do. People will spend a fortune buying unhealthy dogs that are of very little real economic utility, simply because the “pureness” of their breeding confers upon the animals a higher status. A cattle strain that doesn’t produce marketable beef isn’t going to be bred from. But we can breed dogs that die at age 5  and can’t whelp naturally. That’s because people will continue to buy those dogs, regardless of health. The novelty of the breed confers upon its owners status.

(Of course, we can have breeds without having a closed registry or a Potemkin open registry system. But that’s a different discussion.)

Dogs also are derived from a widespread, genetically diverse ancestor that also backcrossed into the population at least several times in the history of its domestication. There are only so many opportunities to bring in new blood for exotic snake species– especially if it is Australian. (Australia banned the export of its native wildlife to private owners.)

So many herp breeders are always looking for new blood. New blood is scarce in relative terms, and the long-term viability of the captive strains depends upon it.

That’s something dogs haven’t yet faced, but their long-term viability is threatened so long as we think that purity is always a virtue unto itself.

It is less of a self-defining virtue than diversity is, for diversity has several important qualities.

Not the least of which is how important it is for the immune system.

But that’s very hard to explain to people who think you can inbreed for health.

Maybe in the short run, but in the long run, it’s a killer.

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The post with the thread that never ends spilled over onto Querencia, where Stephen Bodio quotes Jess’s commentary on that post and the same sort of debate ensued. The debate also moved onto discussing whether we need stricter breeder regulation. It seems that various breeder regulations are being used by the various self-appointed mandarins to harass those who deviate.

Jess recently experienced how far these mandarins will go to cause trouble when the Saluki or Gazelle Hound Club (of the UK) published quotes from her blogs and online commentary in an article  in their publication, The Saluki. They didn’t ask her for her views, but they did manage to publish her e-mail address!

Why can’t we all just get along?

If we can’t have a rational discussion about genetic diversity within the various contrived genetic bottlenecks we call breeds and if all people who deviate from the norms get this sort of treatment, then I don’t think we’re going to get along.

And we shouldn’t.

I don’t care what people do with their lines.

I do care when various pseudo-scientific bromides are used to justify practices and to pillory those who are using science to ensure that their beloved animals remain viable and healthy.

It should be up to consumers to decide which dogs they want, and as consumers, they should be privy to all the knowledge about genetic diversity issues.

But they very often aren’t, and on the ‘net and as a meme within the dog culture, inbreeding is often defended.

And it can be defended, provided one has access to new blood.

Which is exactly what is being denied in the closed registry system.

And now we’re back to where we were.

No way we can get along.

***

Oh and here’s a brindle saluki:

Brindle, for some weird reasons, is controversial in salukis.

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From Discovery News:

Why did the rattlesnake cross the road? It didn’t, says new research, and that may be a problem.

New DNA analyses of rattlesnakes in New York State finds that even minor roadways deter snakes from crossing the road to breed. Populations are becoming isolated from each other by roadways, which may threaten their future.

“We worry for the health of these populations because connectivity is so key to responding to environmental pressures and avoiding inbreeding,” said Rulon Clark of San Diego State University, who led the study published in Conservation Biology. The reduced genetic diversity that results from inbreeding makes populations less resistant to diseases or other disturbances.

Groups of up to dozens of rattlesnakes hibernate together in common dens, which serve as a home base. Come spring, they leave to hunt, and males strike out for neighboring dens to mate with females before returning to their home dens for winter.

The males’ visits to nearby dens provide the genetic mixing necessary to keep a population from becoming inbred.

Clark and colleagues wanted to test whether roads were affecting the males’ mating journeys. They collected blood samples from timber rattlesnakes in 19 different dens in different regions of New York State, including dens separated from each other by roads and others with uninterrupted forest between them.

The researchers analyzed selected gene sequences that mutate quickly from generation to generation to determine how related different snakes are to each other and whether certain dens are mixing with others.

The team found that dens without roads between them acted as a single, connected population, while populations separated by roads showed signs of significantly reduced mixing.

“These roads have been in place for maybe nine or 10 timber rattlesnake generations,” Clark said. “That’s not a long time, but even in that relatively short time frame, we found some very strong patterns. It’s somewhat disturbing to see how quickly the populations lose genetic diversity when they become isolated by these roads.”

Other studies have found that species including bobcats, coyotes and bighorn sheep also change their behavior to avoid roads, with consequences for gene flow. But rattlesnakes may be particularly susceptible, because they avoid roads, and when they do try to cross, the consequences are often fatal, Clark said.

“When they do venture across, they move extremely slowly,” he said. “If they’re disturbed by noise or vibration, their natural response is to freeze and rely on their natural camouflage to hope they won’t be detected. With cars, that’s exactly the wrong response.”

It may be possible to help male rattlesnakes complete their conjugal journeys by building underpasses with surrounding fences that help shepherd the snakes under the roads, the researchers note. Appropriately timed road closures during the migratory season could also help.

Kenneth Dodd of the University of Florida in Gainesville agreed that roads are a threat to wildlife, especially snakes, and that methods to help animals cross roads safely should be implemented.

At the same time, Dodd thinks other forces are at work in explaining the genetic differences among rattlesnakes in this area. Dodd was part of research that analyzed some of the same dens as the new study but found less dramatic effects.

“It’s more complicated,” he said. Small population sizes and localized differences in habitat and topography may also be contributing to the separation of populations, not just roads, he explained.

“We believe that the roadway contributes to genetic structuring of the population, but it is not the sole driving force.”

Yes. I know it didn’t say a word about West Virgina, but not only is the timber rattlesnake our only endemic rattler, it is our state reptile.

In retrospect, I don’t know if that was the best choice.  It is hard to get people to appreciate a place that celebrates a venomous reptile.

Then this article really steps in it:

The timber rattlesnake was selected for the state reptile designation by a group of Hampshire County Middle School students. Their teacher tells me he would have picked the box turtle. However, the rattler isn’t a bad choice. Aside from the obligatory snake-handling church jokes it might generate, the timber rattler is a lot like a true West Virginian.

The timber rattler is generally not aggressive, but when you mess with one–be ready for a fight. The rattler lives its life in rugged confines and is an apt mountain survivor. The rattler is often reviled and misunderstood, but always commands respect.

Yes, and they are apparently quite inbred because they won’t leave the hollers where they were born. Do we really want to have that animal representing our state?

I was hoping they had a good reason to make them the state reptile. Maybe it would make people appreciate them more and not want to shoot them or chop them up with hoes and shovels (a very good way to get bitten).

But no.

I just hope they make the mountain cur the state dog. One politico wants the beagle (which is from England!) to be the state dog. The mountain cur fits the bill very nicely, and it’s native to the Trans-Allegheny West and the Ohio Valley.

***

All joking aside, this article shows that there are real consequences to reduced genetic diversity in the wild. These timber rattlesnakes are very much like breeds in a closed registry system, and the biologists are very worried that they could suffer some problems from their depauperate gene pools.

If biologists think about these issues when dealing with the conservation of wild animals, why is it so hard to get dog people thinking about them?

I suppose it is an apple to oranges problem. These snakes represent biodiversity, and they have some role in the ecosystem. Dogs are mostly pets. They have no utility beyond the emotional benefits they give their owners.

But if we are thinking about this long term, dogs and timber rattlesnakes aren’t that different. They are both organisms with genes. They are animals that are still subject to Darwinian pressures, even if we shield dogs from most of them. Dynamic gene pools allow animals to survive changes in the environment. That’s why sexual reproduction evolved. This type of reproduction creates diversity that allows these animals to be more resistant to these changes.

Of course, I’m not predicting some collapse of  domestic dogs that result from environmental changes or epidemics. But it is a possibility. And at some point, reduced genetic diversity leads to very low levels of fertility. And then dogs would become like giant pandas or cheetahs. I hope it doesn’t get that bad, but that is where this will all lead if we are not careful.

And then we’ll have to find some other canid to domesticate and turn into a new dog. Black-backed jackals get my first vote, and bray foxes get my second. (Modern wolves are just too hard for the average person to handle, so I don’t think we should consider them. And coyotes are paranoid. Not good candidates at all.)

Of course, I hope it never comes to that.

But if we can worry about genetic diversity in a poisonous snake, I think we at least owe it to our dogs to at least give the diversity and sustainability of  their gene pools some consideration.

***

Now, I would be remiss if I didn’t mention another aspect of West Virginia’s relationship with the timber rattlesnake.

I don’t know if you’ve heard of these churches, but we have congregations in West Virginia that pick up snakes. Because these are Pentecostal churches, there is a lot of movement going on (and speaking in tongues). When you add people holding venomous snakes, it gets a little interesting.

Source.

Jolo is in McDowell County, West Virginia, which is the southernmost county in West Virginia. It’s where Homer Hickam, Denise Giardina, and Jeannette Walls grew up.

And before you start stereotyping, Obama beat McCain there.

West Virginia is a complex place. It gives some of us complexes.

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