Understanding Autosomal Recessive and Autosomal Dominate traits.
Autosomal recessive is one of several ways that a trait, disorder, or disease can be passed down through families.
An autosomal recessive disorder means two copies of an abnormal gene must be present in order for the disease or trait to develop.
(Both parents each must contribute one copy of the abnormal gene.)
Source: Read more HERE
Autosomal dominant is one of several ways that a trait or disorder can be passed down through families.
If a disease is autosomal dominant, it means you only need to get the abnormal gene from one parent in order for you to inherit the disease. One of the parents may often have the disease.
Source: You can read more HERE
Autosomal Recessive Disorders:
In the case of a simple autosomal recessive disorder (in other words, a disorder caused by a single, recessive gene that is not sex-linked) for which a test for carriers is available, the recommendation is to test your breeding-quality stock, and breed carriers to normal-testing dogs. The aim is to replace the carrier breeding-animal with a normal-testing offspring that equals or exceeds it in quality. You don't want to diminish breed diversity by eliminating quality dogs from the gene pool because they are carriers. As each breeder tests and replaces carrier dogs with normal-testing dogs, the problem for the breed as a whole diminishes.
Autosomal Dominant Disorders;
Autosomal dominant genetic disorders are usually easy to manage. Each affected dog has at least one affected parent, but it can be expected that half of the offspring of an affected dog will be free of the defective gene. With disorders that cause death or discomfort, the recommendation is to not breed affected dogs. To produce the next generation of a line, a normal full sibling of an affected dog can be used, or the parent that is normal can be used.
A problem with some autosomal dominant disorders is incomplete penetrance. In other words, some dogs with the defective gene may not show the disorder. Roughly half their offspring, however, may be affected. If a genetic test is available, this is not a problem. Otherwise, relative-risk assessment can identify which dogs are at risk of carrying incompletely penetrant dominant genes
Source: Breeding Strategies for Managing Genetic Traits
Jerold S Bell DVM, Clinical Associate Professor of Genetics
Tufts Cummings School of Veterinary Medicine
Primary Lens Luxation
Primary Lens Luxation (PLL) is Autosomal Recessive and very easy to control and mange IF you test your breeding stock.
Plase, do not pay heed to ANY breeder casting stones at others that test. It only shows you that they have no idea what is going on. They can't show you any OFA results for any testing of dogs. They can't show you any carries of PLL, BUT thay can't show you any dogs that are clear either. How can they show you any bad results or GOOD when they do not test for anything at all.
They are happy to sit back and think they look ok becuase they didn't test and cast stones at those that do. How foolish is that? What they want to do is take the attention of themselves and their lack of testing by showing you less then perfect results done by breeders that DO TEST.
For us, testing is NOT about always removing dogs, but about breeding SMART. That starts with knowing what you have and making an educated decision for each and every dog and each and every cross.
Primary Lens Luxation (PLL) Clear Kennel
KnD has a goal. Well, we have many goals when it comes to these great little animals we call "Rat Terriers", but this goal I am talking about is a PLL clear kennel. Like I said though, it's not our only goal. We won't give up good qualities only to boast that we have all PLL clear dogs. This genetic issue can be controlled with a simple one time DNA test. If we test and breed wisely we can keep our good qualities and breed away from this issue, but we won't do it at the expense of loosing good qualities. PLL can be VERY well managed and easily. I actually worry a bit when I see breeders boasting about this. It is just too early at this point and time to throw away all breeding dogs based only on this ONE manageable issue.
Read more about PLL HERE