Hybrid Vigor is a very useful tool to create healthy individual dogs. In order to create a healthy dogs free from breed specific aliments; pairing and selection of dogs are very specific in regards to health, performance, temperament, and all over type. Hybrid vigor can hide negative traits but only testing and selective breeding can eliminate them from a bloodline. We base our entire program on ensuring the health and genetics of the dogs we produce. Nothing but the best is acceptable.
In order understand how hybrid vigor works you first need to understand a little about genetics. A gene is positioned on something called its locus. All genes have two copies – one inherited from the mother and the other from the father. Different combinations of genes produce different results, and some genes are dominant over others. Some loci are dominant over others, and sometimes genes sitting on different loci are needed for certain genes to show themselves.
The next thing you need to know is all “purebred” dogs are inbred to make them ‘breed true’, or produce offspring that look just like their parents- that’s how breeds are created. This is done in an effort to guarantee pointless traits like the angle of a dog’s forehead relative to the angle of its muzzle, or a solid white coat, a dog would be selected who carried these traits and inbred to its own children and siblings to create a population which also carries these traits. Unfortunately, this inbreeding allows potentially negative recessive traits to surface by removing potentially positive dominant traits from the bloodline.
All pure/inbred breeds carry negative recessive traits. That’s really the key to why hybrid vigor works, these negative recessive traits are recessive.
Negative dominant traits show themselves in any dog who has a copy of that gene, and so are easy to bred against. Of course, most people just don’t breed sick or deformed dogs, however, it’s what’s hiding in their DNA is the real issue. When you hear about different conditions that certain breeds are predisposed to, the recessive traits carried by one or both parents is what they are talking about. Recessive genes “hide” behind dominant ones. You need two copies of a recessive gene for it to be expressed. DNA testing allows us to pair dogs appropriately so these potentially dangerous health conditions are never expressed. Not being restricted to a specific breed allows for a greater diversity in selection so we are able to make selections based on not only health, but type as well. We feel you should be allowed to have the total package without having to sacrifice one thing for the other!
To explain how different disease processes are inherited in dogs, we will look at the condition; Dilated Cardiomyopathy (DCM). DCM a condition that affects the heart and is seen mostly in Dobermans, Great Danes, Boxers and Cocker Spaniels. It is also popping up in additional purebred dog breeds and becoming more prevalent.
How is this passed on in breeds? If both the sire and the dam are carriers, that means they each have 1 copy of DCM on the same locus. Since DCM is recessive and both parents only have 1 copy of the mutation, neither parent will actually be affected by the disease. Each dog passes on one gene at random for each locus. So a perfectly healthy dog that has never had genetic testing can ultimately create a litter of very sick puppies.
That means in a litter, on average:
25% will receive a copy of the normal gene from the sire and a copy of DCM from the dam making them carriers as well
25% will get a copy of the normal gene from the dam and a copy of the DCM gene from the sire making them carriers as well
25% will get two copies of the DCM gene, one from each parent making them affected by the condition
25% will get the normal gene from both the dam and the sire making them healthy
That means 75% of this litter is unbreedable in purebred populations where this condition is prevalent and 25% probably won’t live very long. The worst part is, with conditions we don’t have genetic tests for, there is no way to tell the difference between the normal dogs and the carriers. So these problems just get passed on from generation to generation. When focusing on Hybrid Vigor, you can take a otherwise healthy puppy that is a carrier (remember this means they will not be affected by the condition) and breed that health conditions completely out of your lines by careful selection. Roughly 25% of the litter between a carrier parent and a clear parent will result in carriers only. Over a few generations, all breeding stock will be genetically clear and inherently healthier due to the increase of genetic diversity, lowered COI and outcrossing of disease processes.
The chart below shows visually how this works.
Now back to hybrid vigor. Hybrid vigor is another name for the Heterosis effect. Heterosis just means that the two genes sitting on a locus are different from one another. For instance, If a dog has the black and the brindle gene on its K locus, it shows heterosis. That dog will be black because black is dominant, and will carry for brindle. Some of this dog’s offspring will be black, and some will be brindle. While this is great for gentic diversity, This is not what some show breeders want. They want a “good” stud to produce dogs just like himself. In an effort to get a dog who will only make black dogs they resort to inbreeding to get dogs who have two copies of the black gene sitting on the K locus. The problem is while they are destroying genetic diversity in the coat color the same thing is happening on other loci, allowing negative recessive traits to show themselves as previously mentioned while explaining the inheritance of disease. This leaves the poor show breeder wondering why the healthy dogs he started with are starting to produce sick offspring, as well as smaller litter sizes, smaller breed sizes and undesirable traits.
However, when you cross two different breeds with different recessive traits, it pushes the negative recessive traits back under the dominant genes from the other breed. This is hybrid vigor. This means negative genes for allergies, joint problems, cancer, heart problems, eye problems, etc just “vanish” over time with proper breeding management. This creates a dog with less problems in their health and temperament. Hybrid dogs live longer, go to the vet less, make better mothers, produce more milk, and are more flexible in their training.
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