Line breeding, inbreeding or closebreeding?

[JVZ Boxers]

What would a pedigree with this format be considered?

Sire("James")------------------
P Sire(Half brother to dam)
U Dam("Kristi")(half sister to jenny)
P (Not related to James)
P
P-------
I
E Sire("James")--------------------
S Dam(Half sister to sire)
Dam("Jenny")(half sister to Kristi)
(not related to James)

A half sibling breeding where each parents sire is the same and their dams are half siblings unrelated to the sire.

 

[JulieM]

Depends who you ask. There are no "official" definitions, but I think most would put half-siblings in the inbreeding category.

 

[JVZ Boxers]

Julie,

Don't you think it would be somewhat beetween Linebreeding and Inbreeding?
Which according to Patricia Craige in her book "Born To Win Breed To Succeed" is Closebreeding. I checked her book out from the library so I can't look it up right now but, if I remember correctly she had a sample pedigree that shows what she means by Closebreeding. I beleive that pedigree has a similar format to what I'm suggesting. If I'm incorrect and somebody has this book at home, please explain how the format of this "Closebreeding" was layed out in her book.

Also, do you think that half sibling breedings are "safer" in terms of fixing unwanted traits than true inbreedings? Obviously if one is utilizing half sibling breedings in their program they are trying to "fix" cretain desirable traits. I do understand that by doing so they also run the risk of fixing unwanted traits.

Thanks,

 

[boxer]

I don't think "closebreeding" is a generally accepted term. Possibly even unique to that particular author

The thing about linebreeding versus inbreeding is that exactly where you draw the line between the two is a matter of opinion. As JulieM said though, I think most people would agree that the breeding of siblings or half-siblings together falls in the inbreeding category.

Here's a recent thread that discussed the issue: http://www.boxerworld.com/forums/showthread.php?t=63990

 

[JVZ Boxers]

I think you are correct that the term "Closebreeding" is specific to that author. I have not heard it used in any other book or forum. I will have to admit though, anyone who has done as well in their breeding and showing career as that author is most likley on the right track when it comes to her interpitation of a pedigree. Although in her book she does clearly state that what works for one person may not work for the next. I suppose that this subject is just like any other in this world. Everybody has a different opinion. And that is the reason I started this post. I like to take the opinions of others and pick and choose which information I'd like to keep and possibly use.

 

[boxer]

Also, do you think that half sibling breedings are "safer" in terms of fixing unwanted traits than true inbreedings? Obviously if one is utilizing half sibling breedings in their program they are trying to "fix" cretain desirable traits. I do understand that by doing so they also run the risk of fixing unwanted traits.

I guess that by 'safer' you mean 'less risk' of it occuring - and by 'true inbreeding' something as close as full siblings? Well, then technically the answer has to be yes. The more genes that a pair of dogs share, the greater the chance of obtaining two copies of various genes in resultant puppies. Obviously, that applies to both desirable and non-desirable genes.

But the key to avoiding (as far as possible) fixing undesirable traits and genetic defects is knowing *very* well the lines you're breeding from. That means several generations, so that the breeder concerned has a reasonable knowledge of any (undesirable) recessive genes that are likely to crop up in such a close breeding. Personally, I would be concerned at anyone attempting a full or half sibling breeding in their first two or three generations with a breed - unless they have the close mentorship of the breeder whose line they are breeding from and are *very* well aware of any health issues that may exist within that line

 

[Louie's Mom]

Oh My Gosh!

Ok people, I dont know why you would think its ok to do this, if you replaced the dogs with people - do you think it would be ok for you to have children with your half brother? I really doubt it, Genes are the same weather dog or human - genetic defects come from breeding like this. Just because the siblings look good - it doesn't mean that you can mix them just to get similar looking puppies - it does make them more suseptible to things - Just because professionals do this dosen't mean its o.k.

Charlotte

 

[StormKatz]

Too close for me.

That's just a little too close for comfort to me....but that's just me.

My Donte has a few of the same dogs on both parents sides, but they are three & four generations back.. there is some linebreeding, but nothing anywhere near that close.

 

[gmacleod]

...genetic defects come from breeding like this... it does make them more suseptible to things

I would agree that sibling or father/daughter inbreedings are rather closer than most of us like to see. Personally I'm not even a fan of continuous linebreeding - simply because the long term result is limitations on the gene pool.

But your statement is actually incorrect. Inbreeding or linebreeding will *not* create genetic defects. That is an old wives tale long since disproved by geneticists. Probably a hundred years or more ago. The theory of hybrid vigour persisted quite some time longer, but even that has been well and truely buried by now.

As already noted in this thread, all breedings that close will do is increase the chance that a dog ends up carrying multiple copies of the many genes. And *if* there are defective genes there, then they will become apparent in offspring - because there is no compensation from an non-defective gene. One could argue that that can be a good thing because it enables breeders to identify defective genes in their lines and breed them out - rather than continuing to breed from stock which are carriers.

And that is the reason it is repetitively stated that before going anywhere near such a breeding, breeders need to know their lines inside and out. So that they're already aware of any genetic defects present and that might show up if a close breeding is attempted.