Josey

First, let me say, this is *not* a pointed question, I am truly asking because I know less than nothing about breeding.
I am curious, when looking at pedigrees of show dogs from responsible breeders, about the number of times the same dogs show up on both sides of the pedigree. Isn't this inbreeding? Or is it OK if it is 'X' number of generations removed from the actual breeding pair? Is this what the term "line breeding" means?
I've seen Web site from people who don't appear to be responsible breeders advertise that their pups "aren't inbred like show dogs."
Please explain all this to me!

biscuit

Okay. This is my amateurish attempt at an explanation.

Dog breeds are identifiable as specific breeds because certain traits have been selected for in the process of breeding. As a result, ALL identifiable dog breeds - not simply bassets - are very inbed.

Unfortunately, one of the consequences of being s highly bred is that the risks of transmitting genetically based diseases becomes much, much higher.

Now I don't know the genetics of dogs or whatever, but I'm going to make a guess that a lot of these diseases are recessive traits. So I'll use recessive traits as an example.

If you've taken any biology in school, you should know what a recessive trait is. In essence, a recessive trait may not show up in generation after generation UNTIL two critters (dog, human, whatever

And glaucoma is just one of the genetic disorders for bassets.

I hope this makes some kind of sense. And I sincerely hope someone who can really explain it comes along!!

Betsy Iole

This question is currently the subject of sometimes vigorous debate within the fancy. When stripped of its emotional overtones, it's basically a debate about how best to use genetics and selective breeding to achieve specific goals, and the consequences, good and bad, of various approaches.

Here are some websites that outline the issues.

In-Breeding and other Breeding Methods
Inbreeding and Linebreeding
The Canine Diversity Project
The Price of Popularity: The Use of Popular Sires and Population Genetics
Canine Genetics Resources

Edited, after reading biscuit's post. She does a good job of outlining the basics. Mating of closely related individuals increases homozygosity, reduces genetic diversity, and fixes traits, both good and bad. This is how purebred breeds of today were developed.

OTOH, there is mounting evidence that preservation of genetic diversity is desirable for health reasons. Perhaps nowhere is this more important than at the MHC (Major Histocompatibility Complex) loci. The MHC plays a central role in immune function, and a high degree of genetic diversity is crucial to the long term survival of a population. For more information, see Practical medical importance of major histocompatibility genes in disease resistance and reproduction in dogs and Canine Autoimmune Disease: The Role of the Major Histocompatibility Complex .

[ February 23, 2004, 08:29 PM: Message edited by: Betsy Iole ]

__________________
Betsy, Mom to
CH Bugle Bay's Sin City Caper UD RE TD BHCA-VC
CH Bugle Bay's Sin City Cuppa Joe TD
CH Bugle Bay's AllUCanEat Buffet CDX RN TDX NA CGC BHCA-VCX, 1996-2008
"Bugsie" UDX NA NAJ CGC, 1991-2006

shallhb

Sort of continuing this thread...I've never really understood dog breeding, and yes, I took high school genetics, but they kept talking about pink versus white sweet peas, or something like that, and I drifted off.
. Would it be likely to be linked to other (unhealthy) recessive genes, or what?
Sharon

__________________
Sharon Hall

Grace (puppy in training)
Bella, UD, VER, TD, RE, CGC
Pearl,UD, TDX, RE, CGC (Waiting at the Bridge)
Samantha, Theodore, CGC, Louella, Zeke and Arty, Bassets All; (All Waiting at the Bridge)

Dean

Very simple-- my methods are called line breeding, - if you do the same, it's inbreeding !!

biscuit

Sharon, it's my understanding there's a strong genetic component for human behavior --- think of all those stories of twins separated at birth who meet 40 years later and have the same little bubble hairdo and mannerisms and are both wearing plaid shirts and cordovan loafers!

So, if there's a strong genetic component for human behavior, why shouldn't there be one for dogs?

shallhb

Biscuit,
Yup, I suspect that the traits that go into obedience are certainly in part inherited. There are three basset hounds in Northern California that show in obedience--two are from the same breeder, and the third is closely related to the other two.
What I was trying to say is--if there is a trait or set of traits that are uncommon in a breed, I'm assuming they reflect recessive genes (Come to think of it, maybe that's a wrong assumption--Huntington in human's is dominant and its rare ). Yikes, my ignorance is showing and I'm tangling this all up. Back to what I really wanted to know--would it be unhealthy to breed for a rare trait or set of traits, like an 'obedience' basset.
Betsy??

__________________
Sharon Hall

Grace (puppy in training)
Bella, UD, VER, TD, RE, CGC
Pearl,UD, TDX, RE, CGC (Waiting at the Bridge)
Samantha, Theodore, CGC, Louella, Zeke and Arty, Bassets All; (All Waiting at the Bridge)

Betsy Iole

There's a belief in the breed that good fronts (front assemblies, not obedience fronts ) are "recessive", which I assume means hard to get and hard to keep. (Hmmm, maybe they mean obedience fronts, after all.) Anyway, just because they're regarded as recessive isn't a deterrent to breeding for them.

__________________
Betsy, Mom to
CH Bugle Bay's Sin City Caper UD RE TD BHCA-VC
CH Bugle Bay's Sin City Cuppa Joe TD
CH Bugle Bay's AllUCanEat Buffet CDX RN TDX NA CGC BHCA-VCX, 1996-2008
"Bugsie" UDX NA NAJ CGC, 1991-2006

Josey

Thanks, it's clear as mud!
I wonder, after all that good information, if maybe Dean hasn't struck right at the heart of it?!
So, accepting the basic premise that modern "pure" breeds were developed by inbreeding, does this mean that a show breeder today is "responsible" because while s/he continues to inbreed dogs (as in, maybe one generation removed), s/he only choses dogs that have not demonstrated undesirable traits, such as glaucoma, certain behavioral or conformational characteristics? Does this, as with the glaucoma example, line us up for worse genetic problems down the road, as the more complex (and usually recessive so rare) abnormalities get closer and closer to a double-recessive combination?

biscuit

Hopefully someone will correct me if I'm wrong (which is kind of a given ) but ... I think, in order to avoid glaucoma and similar problems, you need to both refuse to breed pups known to have the disorder in their line AND do genetic testing.

Not all disorders express themselves, meaning not all disorders will actually show up in a line ... until that fateful day. Hey, it happened in my family even. A niece showed up with a rare ... I think it's called an autosomal homozygous recessive disorder. In other words, not a sign anywhere, but apparently my family and my sister's husband's family are carriers -

The same could happen with pups. Which is why the genetic testing is so crucial.

I think, if all parties are responsible, the likelihood of coming up with worse and worse disorders over time is kind of unlikely. I mean, how many generations back do bassets go?

The problem is ... the sheer number of irresponsible breeders. There's where the problems arise.

I think.