I have leanred a lot from this thread

Me too Ive been reading biewer threads for yrs and this one is so informational

I vote for intelligent discourse. Sry have not been able to reply too much as my as my puter is in repair

I also need to print some stuff out for a better understanding

Well, before I read that article, I had assumed that Biewers and Partis were both carriers of the piebald allele at the MITF gene because they supposedly both traced back to Streamglen (is that true, or just a theory that both trace back to Streamglen?). Now that some Partis have tested as "e" at the E gene, I'm not so sure. Biewers are definitely piebald, but maybe some lines of what people are calling Parti are piebald and others are "e"? I don't know--more testing of Partis is needed! Have any Parti breeders here had their dog's coat color genes tested?

What makes a dog lineage a separate breed is a unique appearance and genetic uniformity that is distinct and separates them from other breeds. The 100 Biewers that were tested in the MARS study fit that description because they could be separated from the Yorkshire Terrier group in the Primary Component Analysis. But those Biewers are from Biewer by Biewer matings, so that kind of breeding has kept them separated from the Yorkshire Terrier gene pool. The breeders who cross Biewers with Yorkshire Terriers to create "splitters" are breeding more Yorkshire Terrier into their DNA and they will test to be more like Yorkshire Terriers and may not be separable from Yorkshire Terriers by the MARS test.

To recap:

Beiwer X Biewer = separate breed

Biewer X Yorkshire Terrier = becoming more like Yorkshire Terrier, and are not a separate breed.

Parti X Parti = No data on that, sorry!

Parti X Yorkshire Terrier = becoming more like Yorkshire Terrier and not a separate breed.

Chocolates -- No data on them either, but if they are being crossed back to Yorkshire Terriers, they are becoming more like Yorkshire Terrier and not a separate breed.

The upshot is that these colors were all bred into Yorkshire Terriers from some other breed in the (hopefully distant) past, and just because a dog is a different color, doesn't automatically make it a different breed. What makes a dog a different breed is more than just a single coat color gene--it involves multiple genes on multiple chromosomes that have become fixed by breeding within the emerging breed or population to keep it separate from other breeds, and you have to be able to distinguish the separate breed from other breeds by appearance, behavior, etc.

"Principal Component Analysis," not "Primary Component Analysis," but it's too late to fix by editing.

OK, the Biewer dog must have the piebald gene to be designated as a separate breed???
What other type of chromosomes must be ID'd?? Do they even know or is it a random search to find like chromosomes that are different from the Yorkies?? Do "they" have to ID two or three different dog types mixed with the Biewer to call it separate from the Yorkie? To me it would be beneficial to run another set of DNA tests on the Biewers, Parti's and possibly the Yorkies to research the likes and differences of the 3 breeds.

I am learning so much, and this fascinates me. I am going to read it again to further my understanding of all of this. I hope Thais thread remains open.

I commend breeders who do everything in their power to have healthy babies, no matter which breed we are talking about. The health, temperament, and well-being is of utmost importance to me. I hope we can use whatever knowledge gained to help these beautiful and precious breeds.

Would the piebald gene alone in the Biewer separate them from the Yorkie in the MARS test. And where you saw the fading of the dots back towards the Yorkies PCA are those Biewers that had been bred back to the Yorkie (e.i. F-1 and F-2) ???

Biewers by definition have the white color patches caused by the piebald gene, so that part is taken care of. When MARS created their breed test for the Biewer, they used DNA markers on most, if not all, of the dog chromosomes. Some chromosome segments in the group of 100 Biewers were more like Yorkshire Terrier chromosomes, other chromosome segments were more like other breeds--it was an interesting data set. So yes, they do know which chromosomes are different.

I absolutely agree, it would a fascinating study to do DNA analysis on more groups of Biewers, Partis, and Yorkshire Terriers to see how they are all related, and to see the differences. Hopefully all the different breed groups can get together and make it happen. There is nothing to fear by doing this work, and it will resolve these questions once and for all.

:thumbup::thumbup::thumbup:

At this point in time what makes a dog Purebred
 

I am going to give a lay persons explanation. Always of course understanding that a 100percent breed DNA identification is not done yet.

I will start with my breed brt,s. less than 50years ago this breed got recognized as a new and distinct breed. The development of the bred spanned almost 20 years and included some 20 odd breeds.

As fanciers And judges we did not go on DNA analysis, but on form,function,behaviour,and to a certain extent color.

One keystone prior to recognition is the repeated breeding s for types over many generations.

These dogs breed true to themselves

From the rottie the giant schnauzer the Newfoundland and the Airedale terrier the four main contributors came our breed. The brt.

They bred true to their
Type

You can see glimmers of their ancestors in the blackies we have today.

The old breeders had a vision of what they wanted,which spanned a huge field encompassing size appearance temperament structure and function.

And they patiently bred for that.

And let me remind you all without the benefit of the science we have today!

So to my mind is the biewer significantly different in all those qualities I mentioned?

Then the incoming is this single gene analysis. Does a single gene make or break a breed?

Food for thought

Great question!!! No, the piebald gene alone would NOT separate the Biewers from the Yorkies in the MARS test. The MARS test is based on 300+ DNA markers scattered across the canine genome (dog chromosomes).

Where you see the fading of Biewer dots back towards the Yorkshire Terrier dots COULD be due to some Biewers having more Yorkshire Terrier DNA in them than the Biewers that are more separated from the Yorkshire Terrier group. It could be due to random "genetic drift" during the breeding process, or it could be due to the samples being taken from Biewers that had been crossed back to Yorkshire Terriers more generations. A new study including groups of Biewers from the different types of breeding progams (Biewer X Biewer and Biewer X Yorkshire Terrier), all with well-documented pedigree information, would be informative in answering this type of question.

:thumbup::thumbup::thumbup: Great explanation! I hope that Biewer breeders and owners can step in and answer the first question: Is the Biewer significantly different in those qualities of size, appearance, temperament, structure, and function? For size, I'll give an answer and say no, since they are roughly the same size as the Yorkshire Terrier, but there are many other distinct breeds that are also same size as the Yorkshire Terrier. How about the other traits mentioned?

The second question, does a single gene make or break a breed? The answer is no, but if breeders are seeing "off types" as defined by breed standards, they should do the utmost possible to remove them from their breeding stock. Otherwise the breed will morph and change to be something different. Would anyone else care to answer?

OK we have the piebald gene!!
We definitely have the unique appearance!!
We have the difference in personalities!!!
So now we are back to the genetic uniformity!!!!!!!
Have you seen the MARS tests themselves??? What was the "data set" you referred to??
If we cannot get together to retest the 3 groups, what is our next best option?

Form ? How does It differ? Describe in terms of anatomy, head shape and size ear size set and placement, angulations of all major joints. Function difference?

What was the goal .