Variable Expression

Variable Expression is really a rather simple concept, but its implications are huge for breeders and pet owners who love the breed and want to correctly husband and cherish it.

Here is an example of Variable Expression in action:

What we see here is a fawn mom nursing her brindle pups. Dad was probably brindle, and brindle is a "dominant" gene.

Most of the puppies therefore carry that gene. But the "variance" lies in the different types of "brindleness" this mating produced amongst the pups. In fact, it is safe to say no two of the pups are the exact same "brindle" color.

As an aside, we believe the Boxer Breed is one of the most suitable breeds to "variability"- it is one of the lovely charecteristics of the breed- that they have so much in common personality-wise, yet are very 'individual' or unique when it comes to both looks and expression....anyways back to the subject at hand.

Now as we were saying, one need not be a geneticist to understand how "varaible expression" manifests itself outwardly. However, when we look at some internal implcations, the subject gets a bit more serious.

For example, the same "variability" that causes different shades of brindle in a single litter, can also cause a male with Class I (unsymptomatic) Aortic Stenosis to sire pups with any levels of the same genetic mishap. From the unsymptomatic, to the sudden death, fatal type.

This is no small issue for the breed, for the problem is exponential. That is, all of the pups produced by that sire may go on to produce their own off-spring.

That is why those who truly love this beautiful breed, will always subject their dogs to the most rigorous of genetic screenings before breeding him or her. Not doing so is truly a threat to the long-term existence of Boxers.

In general, whenever you read a genetic disorder has "variable expression" you should think "can I screen for this" before you breed your Boxer.

Not only is it incumbent upon breeders to act responsibly, but it behooves those who are purchasing their pets to ensure BOTH parents have sufficient documentation of their screenings.

OK, time to get off the soap box... (sorry the subject strikes a nerve with us!)

A more scientific definition of "Variation" from a genetic standpoint would be: variances in type and severity/degree of a genetic disorder or trait between individuals with the same genotype, even within the same near-family.

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