Heterosis: (n) Increased vigor or other superior qualities arising from the crossbreeding of genetically different plants or animals.
So, there's this funny term flying
around that sounds official: Heterosis, otherwise known as Hybrid Vigor. When I
first started hearing about it I wondered what it was and decided to look into
it some more. Again, for a more detailed explanation I will defer to Wikipedia or answers.com and I will
simply try to provide a layman's definition that specifically applies to dog
breeding.
ONE PARAGRAPH EXPLANATION:
In general, when two unrelated breeds are crossed, the first generation
resulting from that cross produces a dog that is stronger and healthier that
either of the original parents (or parents breed). Amazingly this seems to
apply to both the health of the animal and their temperament. When you have a
breed that "tends to be..." something negative and you breed it with
something positive, you get something better. GOING A LITTLE DEEPER:
Basically what I have gleaned is that throughout years of breeding owners of
dogs have recognized certain traits in dogs that they like or need and have
bred dogs specifically for that purpose. As more and more people did this over
vast regions the various breeds of dogs developed and were helpful for things
such as hunting, herding or working. Unfortunately as people intervened and
named these breeds they also created a thing called a pure-bred dog. Ultimately
by choosing to only breed dogs to other dogs within the same breed people also
confined the gene pool of that breed to a specific grouping of dogs.
Now, as a nation we recognize that in-breeding of people is not a healthy thing
because defects and diseases are more likely to occur. Originally the pure-bred
breeders had a large enough gene pool that there really wasn't an immediate
problem with disease or defect however as the breeders have become more
aggressive to gain certain traits and continue to exclude new bloodlines in a
breed eventually issues have developed. This is why we know there are certain
issues (like Hip-Dysplasia in Labs) or genetic diseases (like von Willebrand's)
that tend to occur more often in specific breeds.
So, this is where Hybrid Vigor comes in. If a breeder chooses to step outside
the specific gene pool of a purebred dog and cross breed then there is a
natural benefit of expanding the gene pool and allowing the healthy genes of
the unaffected breed strengthen the weakness of the purebred. Since the genetic
disease is the result of a deficiency in the gene pool, it stands to reason
that infusing the gene pool with new healthy options would be a good thing. It
seems this is the case with dogs and the first generation Doodle has been a
great example of the benefits.
OK - this got way longer than I ever
thought it would! I am not an expert in this but am just attempting to explain
what I have seen and read. I hope it has helped. Feel free to dig deeper and
learn more about this on your own!
