" Hybrid Vigour"

[Jed]

Hybrid vigour refers to the mating of different species ... such as lions/tigers; zebras/horses. There are no proper scientific references to "hybrid vigour" occurring when crosses are made within the same species, although there is a lot of non scientific claims on the internet.

[sandgrubber]

1365260436[/url]' post='6167509']

Hybrid vigour refers to the mating of different species ... such as lions/tigers; zebras/horses. There are no proper scientific references to "hybrid vigour" occurring when crosses are made within the same species, although there is a lot of non scientific claims on the internet.

.??? I thought the term originated in botany, where F1 hybrids are usually varietal crosses, and are often robust due to increased heterozygosity. Seed companies love them cause they mess up seed savers...the F2 rarely runs true.

[tdierikx]

There is also the fact that purebreed lines are easy to check back on to see what may be present or lacking... thanks to all the dedicated breeders out there who try to produce the best next generation that they can.

As for crossbreeds, there is very little data about the genetic background of any individual "line", and thusly the argument that they are generally healthier, or more prone to disorders, is pure anecdote.

I think also that more of the general public are more likely to take their purebreed dogs to the vet for any perceived ailment than those who own the generic crossbreed - so the theory is that those crossbreeds not seeing the vet with any regularity are "healthier"... which may not really be the case... or it may be... how can we extrapolate true data if the target group is under represented?

The sheer variety that crossbreeds come in is staggering - pick any two breeds and someone has possibly tried (or succeeded) crossing it - with extremely varied results - even in the same litter.

My personal take on it is that if a prospective puppy owner looks for a breeder (of any pure or crossbreed) does a bit of homework into the genetic testing of their breeding animals, and breeds to enhance the possible long term health of the offspring, then they are more likely to take in a pup that will have the best chance of being healthy for longer than a pup whose breeder just threw 2 random dogs together to make pups for sale.

The other fact - that environment can play a huge part in the development of any dog - seems to be missed when the extremists (from both sides of the argument) put forward their hypotheses... it's not ALL about genetics... genetics is really only the starting point...

T.

[Steve]

There is also the fact that purebreed lines are easy to check back on to see what may be present or lacking... thanks to all the dedicated breeders out there who try to produce the best next generation that they can.

As for crossbreeds, there is very little data about the genetic background of any individual "line", and thusly the argument that they are generally healthier, or more prone to disorders, is pure anecdote.

I think also that more of the general public are more likely to take their purebreed dogs to the vet for any perceived ailment than those who own the generic crossbreed - so the theory is that those crossbreeds not seeing the vet with any regularity are "healthier"... which may not really be the case... or it may be... how can we extrapolate true data if the target group is under represented?

The sheer variety that crossbreeds come in is staggering - pick any two breeds and someone has possibly tried (or succeeded) crossing it - with extremely varied results - even in the same litter.

My personal take on it is that if a prospective puppy owner looks for a breeder (of any pure or crossbreed) does a bit of homework into the genetic testing of their breeding animals, and breeds to enhance the possible long term health of the offspring, then they are more likely to take in a pup that will have the best chance of being healthy for longer than a pup whose breeder just threw 2 random dogs together to make pups for sale.

The other fact - that environment can play a huge part in the development of any dog - seems to be missed when the extremists (from both sides of the argument) put forward their hypotheses... it's not ALL about genetics... genetics is really only the starting point...

T.

1. Theoretically breeders of purebred dogs know their lines and can take into account health issues when they are profiling their pedigree but not all breeders are equal and not all information has been easy to find. ANKC pedigrees have no data on them except where the champs are so a breeder needs to be able to access the info from a variety of other sources.Some care some dont - Its still about the breeder.

2. Theoretically there is potentially as much info about any dog which would be bred with any dog of any other breed.Some people who cross breed know what is in the lines of each dog regardless. It is possible for them to know which genetic diseases are common to both breeds and what they need to test for and they test .Some care most dont. Its still about the breeder.

3. I don't believe I could say I'm confident that more purebred dog owners are likely to take their dogs to the vet than those who own cross breds. People these days pay more for a hybrid and treat them very much like their children.

For me the big deal is that its difficult for people who are not passionate about a breed to understand why every decision a good breeder makes is also about future generations and not just the one hitting the ground. Anyone can pick two dogs and watch them mate and have puppies. Not everyone can consistently breed happy healthy predictable puppies generation after generation.

Thats the difference between a breeder and someone who just breeds dogs. A good breeder takes it all into account , nutrition, environment,genetics etc because they know it all impacts on generations to come. Its still about the breeder.

Edited April 6, 2013 by Steve

[redangel]

Hybrid vigour or not, each parent needs to be healthy themselves to produce healthy offspring.

I fully agree with this. I have spoken to some people I know the veterinary field who say due to the popularity in the breeding of cross bred poodles, cocker spaniels, etc..in large numbers (with a questionable maintenance of lineage ie very close matings, matings of untested dogs carrying recessive things like PRA) many more cases of cross breeds with such conditions are being presented.

In my experience, 99% of all the crossbreds I owned lived into their later teens. One dog I lost at 12yrs. Of my last fifteen years of dogs all purebred, I have owned 6...all but 2 lived into their late teens. One was healthy but developed an osteo issue which saw her pts at 8yrs. Another died of heart failure at 10yrs. Strangely enough these 2 dogs were the only two of the 6 that I had purchased, so my knowledge was limited to what I was told & what I had seen. The other four were bred by me and as I knew several generations that made up the dogs personally I do believe that that made a difference.

I think hybrid vigour might have worked in the past when the odd breeding occurred with the neighbours dog etc..two very unrelated dogs, in many cases crosses themselves. These days in the world of mass producing cross breds two dogs may very well have come from very close lines, if purchased from the same demographic.

I agree with Kirislin it depends on having two healthy parents. I also agree with the comments above that a concientious breeder with personal knowledge of many generations that make up their stock would be more viable in order to purchase a suitable companion.

[tdierikx]

In the days before the word "labradoodle" ever came about, all crossbreeds were labelled just that... crossbreeds or mutts... and in the main, most were apparently great family dogs and had few health issues of the kind we see nowadays...

... then all that changed when certain types of people saw the chance to make a buck by giving crosses fancy names and touting them as some sort of "breed" - rather than a mix.

Remember the good old days when there would be a few FTGH ads in the papers for pups - good luck finding many now... everything has a stupid "breed" name on it and people are charging small fortunes for them... *sigh*

T.

[SchnauzerMax]

Hybrid vigour refers to the mating of different species ... such as lions/tigers; zebras/horses. There are no proper scientific references to "hybrid vigour" occurring when crosses are made within the same species, although there is a lot of non scientific claims on the internet.

From my behavioural genetics textbook "Hybrid Vigour or Heterosis is the increase in viability and performance when different inbred strains are crossed."

[Mrs Rusty Bucket]

Steve - that's like the worst ever lottery win.

Hopefully with new technology - your kids can avoid passing the problem on or there will be tech to manage it so it doesn't interfere with their lives.

Hapsburgs had a lot more than one genetic problem to deal with.

Genes are tricky. Sometimes getting rid of one problem - causes other problems. One gene can express with something really bad and something really good.

My dad actually got my mum's blood type checked - before he agreed to marry her. There weren't DNA tests available then but I'm sure he'd have done that too if he could have. We do have some nasty genetic problems in our family - that various offspring will need to watch out for.

And I think we (humans) may end up with more genetic problems - given that some pheromone studies suggest a man and woman can have the best "chemistry" with a partner of the greatest genetic diversity - unless she is on the pill and then she will pick a partner with the least genetic diversity. I'd love to see the follow up study on that, the one that checks actual couples, instead of just t-shirt sniffing.

There is so much more to know in this field. I just know that puppy sellers that claim "multigenerational breeding" to guarantee traits and also claim "hybrid vigor" at best - don't know what they're talking about and at worst - are fibbing in the name of marketing. You just have to google some designer breed names - to see web pages with this kind of fib on them.

[Jed]

1365260436[/url]' post='6167509']

Hybrid vigour refers to the mating of different species ... such as lions/tigers; zebras/horses. There are no proper scientific references to "hybrid vigour" occurring when crosses are made within the same species, although there is a lot of non scientific claims on the internet.

.??? I thought the term originated in botany, where F1 hybrids are usually varietal crosses, and are often robust due to increased heterozygosity. Seed companies love them cause they mess up seed savers...the F2 rarely runs true.

Yes, the term originated with botany

[Jed]

Hybrid vigour refers to the mating of different species ... such as lions/tigers; zebras/horses. There are no proper scientific references to "hybrid vigour" occurring when crosses are made within the same species, although there is a lot of non scientific claims on the internet.

From my behavioural genetics textbook "Hybrid Vigour or Heterosis is the increase in viability and performance when different inbred strains are crossed."

When was the book published, and how much credence does the author have?

[BJean]

Hybrid vigour refers to the mating of different species ... such as lions/tigers; zebras/horses. There are no proper scientific references to "hybrid vigour" occurring when crosses are made within the same species, although there is a lot of non scientific claims on the internet.

From my behavioural genetics textbook "Hybrid Vigour or Heterosis is the increase in viability and performance when different inbred strains are crossed."

When was the book published, and how much credence does the author have?

:)

[minimax]

Hybrid vigour refers to the mating of different species ... such as lions/tigers; zebras/horses. There are no proper scientific references to "hybrid vigour" occurring when crosses are made within the same species, although there is a lot of non scientific claims on the internet.

From my behavioural genetics textbook "Hybrid Vigour or Heterosis is the increase in viability and performance when different inbred strains are crossed."

When was the book published, and how much credence does the author have?

:)

Probably more than wikipedia.

[BJean]

Hybrid vigour refers to the mating of different species ... such as lions/tigers; zebras/horses. There are no proper scientific references to "hybrid vigour" occurring when crosses are made within the same species, although there is a lot of non scientific claims on the internet.

From my behavioural genetics textbook "Hybrid Vigour or Heterosis is the increase in viability and performance when different inbred strains are crossed."

When was the book published, and how much credence does the author have?

:)

Probably more than wikipedia.

You'd hope so for a text. But you never know.

[sheena]

Hybrid vigour refers to the mating of different species ... such as lions/tigers; zebras/horses. There are no proper scientific references to "hybrid vigour" occurring when crosses are made within the same species, although there is a lot of non scientific claims on the internet.

From my behavioural genetics textbook "Hybrid Vigour or Heterosis is the increase in viability and performance when different inbred strains are crossed."

When was the book published, and how much credence does the author have?

:)

Probably more than wikipedia.

You'd hope so for a text. But you never know.

With cattle, farmers (& I am one) get hybrid vigour by breeding two carefully selected different breeds of cattle together, but they are still the same species of animal ie cattle. Difference between cattle & dogs is that any of the offspring in cattle that don't live up to expectations are culled out. That doesn't happen with dogs. A hybrid in the plant world is two plants of the same species eg. tomatoes being crossed together..the resultant plant becomes a hybrid. When one species of animal or plant is crossed with another completely different species eg. sugar cane & fish, then it is genetically modified (GM)

[LizT]

My simple answer if I don't wish to get involved in an all out discussion over the wonderful merits of Designer Dogs is this:

TRUE hybrid vigour only exists in Darwins "SURVIVAL OF THE FITTEST", only through NATURAL SELECTION does the strongest, the best, the hardiest and healthiest survive to breed on.

[inez]

Inbreeding did not help many of the European royal families.

http://en.wikipedia.org/wiki/Prognathism#History

You forget it was an outcross that introuduced the defective gene though.

"It is alleged to have been derived through a female from the princely Polish family of Piasts, its Masovian branch. The deformation of lips is clearly visible on tomb sculptures of Mazovian Piasts in the St. John's Cathedral in Warsaw. However this may be, there exists evidence that the trait is longstanding. It is perhaps first observed in Maximilian I (1459–1519)."

Edited April 8, 2013 by inez

[mita]

The other fact - that environment can play a huge part in the development of any dog - seems to be missed when the extremists (from both sides of the argument) put forward their hypotheses... it's not ALL about genetics... genetics is really only the starting point...

T.

A good point, T. Genes aren't simply all going full bore. In certain cases, the environment supplies the trigger. Along with the fact the environmental contribution to health problems is on a scale of extent.

Also still much remains a mystery as to any genetic vulnerability, or gene involved or combination of genes in numbers of specific conditions.

One powerful thing, as you say, is that the purebred breeding system allows for searching by breadth & depth of pedigree over life spans that are shorter than humans. Which is why researchers in human medicine re conditions that we share with dogs, find such tracking a great boon.

Edited April 8, 2013 by mita

[Aidan3]

"Heterosis was first described by Charles Darwin in 1876 after he observed that progeny of cross-pollinated maize (Zea mays)were 25% taller than progeny of inbred maize [4]. The phenomenon was rediscovered independently by George H.

Shull and Edward M. East in 1908." Hochholdinger, F. & Hoecker, N. (2007). Towards the molecular basis of heterosis. Trends in Plant Science, 12, 9.

"Additionally, producers discovered that hybrid vigor was indeed possible — and very economically beneficial — when many of the new breed lines were used in systematic crossbreeding programs (Dickerson, 1970, 1973)" Green, R. D. (2009). ASAS Centennial Paper: Future needs in animal breeding and genetics. J. Anim. Sci, 87, 2.

[SchnauzerMax]

Hybrid vigour refers to the mating of different species ... such as lions/tigers; zebras/horses. There are no proper scientific references to "hybrid vigour" occurring when crosses are made within the same species, although there is a lot of non scientific claims on the internet.

From my behavioural genetics textbook "Hybrid Vigour or Heterosis is the increase in viability and performance when different inbred strains are crossed."

When was the book published, and how much credence does the author have?

:)

Probably more than wikipedia.

You'd hope so for a text. But you never know.

Plomin, R., DeFries, J. C., Knopik, V. S., & Neiderhiser, J. M. (2012). Behavioral Genetics (6th ed.). New York: Worth Publishers.

Robert Plomin, PHD is MRC Research Professor of Behavioural Genetics at the Institute of Psychiatry, London.

John C DeFries, PHD is Professor of Psychology at the Institute or behavioural Genetics, University of Colorado, Boulder.

Valerie S. Knopik, PHD is Associate Professor of Psychiatry & Human Behavior and Behavioral & Social Sciences at the Waren Alpert School of Medicine, Brown University.

Jenae M. Neiderhiser, PHD is Professor of Psychology at Penn State University.

Plomin and DeFries have been working together for over 30 years and are known for their longitudinal studies of twins viz. The Colorado Adoption Project.

[corvus]

You forget it was an outcross that introuduced the defective gene though.

While heterosis isn't well understood, it is assumed that the effects come about through increased genetic diversity resulting in fewer homozygote traits. It's a fair bit more complicated than a single disease-causing gene defect introduced into an already inbred population. That's just pot luck, really.

It's not very hard to type "heterosis" into Google Scholar, slap on a publication year filter, and see where the peer-reviewed science is at on this at the moment. It does not at all seem to be limited to crosses between species. Nor is it confined to natural selection.

Personally, if people want to justify their positions re: dog breeding with reference to hybrid vigour, that just makes me think they don't know what they are talking about and leave it at that. I'm not about to give them a lesson in inbreeding coefficients or population genetics. It's a waste of time. Smile, nod and walk away is my advice. There is that much misinformation being spread around from all sides it seems like a little more won't make a shred of difference.