I haven't replied to the hybrid discussion as it didn't seem relevant to this thread, but crossbreed dogs are hybrids.

The quote below comes from  a New Zealand government publication at this link http://www.ermanz.govt.nz/resources/publications/pdfs/ER-IS-03-01.pdf

"What is a hybrid?

A hybrid is an organism resulting from a cross between genetically different parents. Hybrids can arise from crosses between closely related species (interspecific hybrids) or by crosses between different types (subspecies, varieties, cultivars) within a species (intraspecific hybrids).

Hybridisation occurs naturally, but it is also widely used in selective breeding programmes for both plants and animals. The mule is an interspecific hybrid between the horse and the donkey, bred to combine some of the favourable characteristics of each parent. Intraspecific hybrids often show "hybrid vigour" (heterosis), growing more vigorously and yielding more than in-bredlines."

Hence, mixed dog breeds such as Labradoodles are 'intraspecific hybrids' (ie are within species breeding) and do show hybrid vigor or heterosis."

This is also quite an interesting article http://articles.directorym.net/Hybrid_Vigour_With_Mixed_Breed_Dogs-a943738.html

I won't bore you with loads of links. While wikipedia articles can't be taken as gospel, they're a great place to start, which I why I posted that link.

> A hybrid is an organism resulting from a cross between genetically different parents. Hybrids can arise from crosses between closely related species (interspecific hybrids) or by crosses between different types (subspecies, varieties, cultivars) within a species (intraspecific hybrids).

> Hence, mixed dog breeds such as Labradoodles are 'intraspecific hybrids' (ie are within species breeding) and do show hybrid vigor or heterosis."

Actually they are not, the hybrids are from different subspecies ie Lion & Tiger, all domestic dogs are from the same sub species of the species Canidae A Wolf x Domestic do would be a hybrid because the Wolf is a different sub species.

All dogs have the same genetic base makeup & therefore of the same sub species & ergo crosses between them are not hybrids. You are only looking at the phenotype of the dogs & not the genotype

"You are only looking at the phenotype of the dogs & not the genotype "

No I'm not - the New Zealand Government is. :)

The second link is to an article written by a certain cross' breeder so not very scientific and likely to be biased don't you think ;)

Okay this is getting tedious now! :)

Here is a link from the University of Pennsylvania School of Veterinary Medicine - unbiased enough for you?
http://cal.vet.upenn.edu/index.php?page=effects-of-inbreeding

Crossbreed dogs are hyrbids, at least for the purposes of discussing heterosis (hybrid vigour). We could go round for days on this one, so I'm not going to keep posting on this.

Yes "It should be understood that inbreeding per se does not cause defects" taken from this link

Thing is without purebreds there would be no hybrid vigour,a nd this only lasts the one generation, so is pointless really.

So surely aiming to produce healthy purebreds is the way to go?