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Originally Posted by wayne2075  Hi, again. I had many requests to continue and share about genetics of the Chocolate yorkie. Maybe we can start over without the negative comments that disrailed the thread. You may not agree with people raising fox or mink for fur this is not the issue. They have learned many things about genetics that the dog people do not know. I believe the color genetics are the same for the fox as it is for our yorkies. We can learn what they have learned without rejecting all of their knowledge because we disagee with what they are doing. What I am going to share will benefit those breeding the parti, goldens, chocolates etc. even though some disagree with those who are doing so instead of the standard yorkie.
I stated in my previous treads that the Chocolate had to be a mutation color and had many dissagree. I am still trying to find the cause of the mutation and still believe it to be chemical or virus. Wild fox in nature are red with white markings. When a western red and a eastern red fox [ two different lines] are bred together they produce some offspring that is a red fox with a black sholder and back with more black markings than white. So when we mix two different lines of the Yorkshire terrier some color changes may happen also. This is some of the reason that yorkie breeders are careful to breed within their lines. There are also a possibility that breeding off line will increase size. Many yorkie breeders have developed their own line and will not breed off this line.
The wild red fox also produced the black fox or silver fox. These were captured and developed in the fur ranching business. Over many years the Black fox became the dominate gene for ranch fox just as our standard yorkie has become the dominate gene. Over the years a mututation would occur such as the pearl fox [a blue gray] and the cinnimon fox [the chocolate]. When the chocolate or pearl was bred back to a black the offspring would be black but would be a recessive gene for chocolate and pearl. This is the simple genetics most understand. They are now carriers. What my question was what caused the color to mutate in the first place. There were no brown or blue gray red fox in nature.
Developing colors from the Chocolate and Pearl gene: a black or standard yorkie that is a carrier for chocolate bred to another black carrier of chocolate will produce about 50% chocolate. A standard non carrier of Chocolate bred to a carrier gene chocolate will produce 25% chocolate offspring. When the Chocolate and Pearl are bred together both mutated colors there is a wash in the colors. It produces Amber. Amber then bred to a Red can produce a washed out cream with a red stripe which can be developed into a strong gene when bred together. There is the leathal gene factor for white. Those who are breeding yorkies for chocolate or golden need to be very careful not to inbreed to establish their line as they may cause other genetic defects as some of the standard yorkie lines have. I am still looking for the answer to why I would have 2 chocolate puppies from lines that have no chocolate carriers. I know that this a true mutation but what caused it. I have been reading a lot of info on what causes mutation. When I stated in my first thread about plastic or rubber from ai could have been the reason. Could be chemical or virus? I probably won't find the real answer. Wayne |
I don't think it was a chemical reaction, but probably a recessive trait somewhere in the line. Remember, you need two recessive traits for the particular characteristic to "show" or display itself. If the other dogs just had one gene, no one would be the wiser. Also, you must remember that color is the result of two genes. There may be other genes that affect that color as well, and I think the chocolate is probably effected by the gene that has something to do with pigment because the dog's nose is also brown. Even a pure white Maltese has a black nose. Remember, on any given trait, there are different genes that determine the final look. For example, with eyes, there are two genes for color, two genes for intensity of that color, or perhaps what's known as pigment, two genes for size of eye, and more genes for shape of eye. So with hair color, it's just not a matter of the two genes responsible for this, but their combination with other genes. Read this link to see how genes are connected to get the final result.
Eye Shine
I do have to add, Yorkietalk is mainly made up of members who are not breeders, we do have a breeding forum, but so many times questions such as the one you pose have been a means to selling the new members dogs, and not really a legitimate question. I think on your second thread, several members gave links to scientific articles you could read on genetics. Most universities have libraries open to the public for in-house reading, and there is so much scientific genetic research literature, however, I'm not really sure scientists have found all the answers you are looking for. This is really not about opinions, it's about facts, and I think you are really overestimating what this forum can do for you.