Did I forget to say that showing dogs is also part science? Humans, and dog breeders in particular, have taken the laws of chance and probability out of genetics--At least most of the time, breeders make the decisions about which stud dog will impregnate which brood bitch to produce a litter of puppies. No laws of probability there.
But the bad news is that making puppies still involves genetics, and by definition we still have several laws of probability involved there. We don't know or control which sperm cell is going to impregnate which egg cell, so until that actually happens and we see the final results we are still working with probabilities! td> >Just because both of my parents were Champions, what makes you think I should become one too?
So how does a newcomer learn about all of these genetic issues and get to the point where they can begin to make informed breeding decisions? The short answer is that it takes a lot of hard work. One of the ways that you can help make it easier for future generations is to be open and honest about what you personally know about the health and genetic issues in your blood lines. The problem is that half-truths and misdiagnosed information introduces errors into any genetic-based decision. In fact, wrong information is much worse than no information when trying to make a breeding decision.
When trying to improve your knowledge about genetics, look for the best qualified teacher that you can find. The best teacher will have a superior understanding of the science, but will also have a special talent for explaining the science. Watch out for the expert that tells you it is too complicated or the good hearted friend that tells you how simple it is.
Another important point has to do with genetic testing.
The STCA Health Trust was established in 1994. The HTF mission is to help provide funding research and study of diseases and genetic defects affecting the Scottish Terrier. The HTF also helps with STCA Member Education programs and keeps the members informed of the latest advancements in genetic testing and disease treatment programs. The HTF helped develop the first truly conclusive (i.e. DNA) test for vonWillebrand's Disease (vWD) and is already working on genetic tests for CMO and Scottie Cramp.
Just when you thought you knew everything—Can you explain these stories based on your understanding of genetics?
Genotype versus Phenotype:
Biology Student: I was in discussion today with a fellow student who said that they had learned in their science class that all fetuses are female until 3 months then the determination is made by a chemical change. I had always been under the understanding that sex is determined at the time of conception. Could you please clarify this?
Instructor: Actually you are both right. The sex is determined by the chromosomes of the male sperm cell, at the time of conception. However, development of a fertilized egg is the same for male and female, until at a certain stage, due to the genes on the Y-chromosome. Male fetuses start to produce substances that change the development to follow the 'male' course.
In fact, you are hitting a difference in 'genotype' versus 'phenotype' here. At conception the fertilized egg has the genotype of either male or female, but the phenotype (the 'form' you see) is not yet apparent. The difference between genotype and phenotype is crucial in biology but it is often ignored.
Genetics versus Environment:
An organism’s phenotype is all of its observable characteristics—which are influenced both by its genotype and by the environment.
A change in the environment also can affect the phenotype. Most people think of flamingos as being long legged, pink birds. But pinkness is not encoded into their genotype! It is actually the food they eat that makes their phenotype either white or pink.
Selective Breeding can have Unexpected Consequences:
As reported in a scientific journal that I read while sitting in my veterinarian's waiting room.
A group a scientists in Russia reported that they noticed unexpected consequences when selectively breeding a pack of wild foxes. The sole selection criteria was a demonstrated tendency towards domesticity (failure to run away when approached to willingness to eat from hand). The unexpected consequence, a higher than average appearance of blaze and star markings (as seen on domestic cows and horses)!