Author archives: Martine Huslig

As a continuation of my last blog related to reasons that breeders give for not needing to do genetic testing, I felt that one of these deserved an entire blog of its own. Some breeders will say, "no problem has ever occurred in this family of dogs and I have been breeding this line for 20, 30, 40 years. I don't need to do genetic testing." From my perspective, these breeders either have not been looking very hard, aren't being particularly forthcoming, or denial is a wonderful thing (and a river in Egypt). When I started getting involved in what was referred to as a "very healthy breed" (per the people who had been breeding them for 20, 30, 40 years), I recognized 3 problems in my first 2 dogs that I would consider "genetic". I had not been told to look out for or ask about any of these issues in my extensive research on the health of the breed. In fact as I was at the breeder's home being told of this issue in my new puppy's mother and grandmother I was thinking, "Gee, that is a genetic problem that no one ever told ...

Many people with a "cute little dog" who are going to breed it to their friend's "cute little dog" and sell the puppies will say, "I don't need to do genetic testing on the dogs/parents, I am not a breeder." If you plan a litter of puppies, you are a breeder.

Other people will say, "There is nothing wrong with the mother and father, they are perfectly healthy. I do not need to do genetic testing." Carriers of genetic problems are often invisible and without testing; you cannot predict whether your litter will be at risk for disease.

Some people will say, "I am only breeding pets and I have never seen any issues in the puppies I produce. I do not need to do genetic testing." Pets are just as likely to get the genetic diseases associated with their breed as show or working dogs and in any scenario, people are quite obviously emotionally attached to their pets. $53.33 billion was spent in the US last year on pets with $13.67 billion of that spent on veterinary care alone (source). Many genetic issues do not get diagnosed as a genetic issue or may develop ...

There is a trend in the dog world for people to create a list of health clearances on their dogs as long as their arm. There is certainly nothing wrong with a long list of health clearances if those health clearance are valid for the breed - and that is a big if.

I spoke in a previous blog about the fact that not all diseases that appear to be the same are the same. An extremely involved genetic disorder can appear to be identical in two affected individuals, yet can actually have extremely different causes. More specifically, it can be caused by different gene mutations or even two entirely different genes. In the previous blog we discussed the different types of PRA that have been found in different breeds.

With a slightly different focus I want to discuss specifically how this affects the "accuracy" of genetic testing. We all know genetic testing is "very accurate." But that assumes you are testing for the right thing and that the specific gene test is informative. One example is the melanophilin gene. Two different mutations related to this gene have been identified to be associated with dilute coat color (called blue or the ...

Many people have misconceptions about genetic terms and what these terms mean related to the inheritance of a health issue in a dog, a family of dogs or a breed. I wanted to take a moment to step back and discuss some of these commonly used terms to help people understand them more clearly.

Most genes (and the genes that will be tested for at Paw Print Genetics^™ ) are located on the chromosomes contained in the nucleus found in most cells. Chromosomes come in 39 pairs (and thus, the genes come in pairs). One through 38 are the numbered pairs (called autosomes) the 39th pair are the sex chromosomes; females have two X chromosomes and males have an X and a Y chromosome. The X is larger and has more genes. Because males have only one copy of the X chromosome (and therefore only one copy of many genes found on the X chromosome), they are at risk of having certain diseases that are unlikely to affect females.
Autosomal conditions are found on one of the numbered chromosomes and X-linked conditions are found on the X chromosome. Each gene has a particular location on the chromosome called a locus. Different ...

Continuing the series on "when genes don't make sense," let’s talk about probabilities. Many people will hear that if a condition is recessive that one in four puppies will be affected or, if it is dominant, that 50% of the puppies will exhibit the trait or be affected with a condition. They will subsequently declare that because the outcome in their litter is different than these exact percentages, it therefore must not be… recessive, dominant or genetic at all.

On the other hand, many people in dogs will say things like "they need to breed a male in order to determine if he produces males or females."

These are different errors in reasoning relating to the same type of probability.

In the first case, people are expecting the actual results to be exactly what is predicted based on possible results or probabilities. In the second case, people are assigning meaning to the random variation that is usually observed (and actually expected) compared to what is predicted based on probability.

To start with the second scenario, millions of sperm are swimming as hard as they can to fertilize the eggs. Roughly 50% of these sperm carry an X chromosome ...

Another non-intuitive but common behavior of genes is that one gene can have different but apparently unrelated effects. This is somewhat the opposite of different genes having the same effect (discussed in my previous blog). Making it even more confusing, the same condition could have both at work!

One gene may create a specific appearance but can also cause issues that would not necessarily appear to be related. In scientific terms the word pleiotropy is used to refer to the phenomenon "when one allele or pair of alleles has different effects - particularly when these effects appear unrelated."

Many examples of this phenomenon exist in the dog world. With on-going research, more will no-doubt be identified.

The gene causing Merle color pattern increases the chance for deafness and eye defects. Certain "white" dogs also have increased risk of deafness related to being white. In other breeds, very white appearing dogs (due to other genes) and dogs with albinism have no associated risk for hearing loss. In the case of the Merle and "white piebald" associations the effect begins on cells derived from the neural crest affecting both pigment, auditory and potentially other neural-derived cells, but not all Merles, double merles and ...

One of the key issues that people often have in grappling with genetics disease is the fact that genes and disorders that are supposedly genetic don't always make sense (or at least not the sense that people expect them to make.) What they see occur does not pass their intuition or logic of what they think they should see if the condition is really "genetic."

A problem will be identified that has never occurred before and people will say in all honesty---"that has never happened in my line" and yet they are told it is "genetic." This happens in human families as well. A genetic condition is diagnosed in a child and the first thing that both grandmothers say is "that did not come from our side of the family!" In some cases they may be wrong and in others they may be right. Different genes follow different "rules."

Recessive disorders in fact come from both families and are due simply to the fact that both the sire and dam happened to carry the same detrimental recessive gene. These can be passed on for many generations unrecognized and only revealed when two carriers happen to mate AND both ...

Why? For the love of dogs. There is nothing more heartbreaking than when a dog that is loved and has been invested in dies. This is heart breaking when that dog has lived a long full life beyond the expectancy for his size and breed and when that dog has fulfilled many hopes and dreams planned for them. It is far more devastating when that loss is premature due to genetic disease. It is devastating when a much anticipated and planned for litter results in a puppy or puppies that die at a day or weeks old. It is worse still when serious problems occur at a year or two years of age, when that puppy is already a part of their owners' life, plans or family. Whether a beloved companion, part of the family, a beautiful show prospect full of potential, a working dog where hours upon hours have been spent in developing their inborn skills to serve an important purpose, or a performance dog trained to (or not quite to) perfection (as the case may be for many of us) it is tragic when this time, energy, love, hope, money, potential is dashed due to premature death or ...