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White Patches of Labrador Retrievers/Goldens?

   
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Oz

Just try to say- No to this face		 
 
Barked: Thu Jul 31, '08 11:29am PST 
Alright! Thanks so much! That is probably the best career advice I have received in a while! smile
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Sadie

Sassy and Shady		 
 
Barked: Mon Aug 4, '08 1:13pm PST 
This question is of great interest for my breed and I have a few questions.

Lacys are always supposed to have white on at least one paw and white on the chest. The white on the paw is not suppose to extend on to the leg but the white on the brisket can extend from the chest to the groin. Any white on the face, the tail, or above the midline is a disqualifying fault. You can see a variety of acceptable white markings in this picture: http://www.flickr.com/photos/julieanna/2732505144/. One is just a small patch, one is a little larger and is seen on the chest, the other is rather expansive.

So, how do genetics play into this type of marking? When does it move from a developmental to genetic issue? There are some dogs that have been known to throw more white into their liters than others. One concern is how to limit this excessive white in breeding programs. Anyone have ideas?
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Gio

CD RE (CKC) RACL- (CARO) FM CGN- SJATD HIC
 
 
Barked: Mon Aug 4, '08 1:27pm PST 
The markings that you are describing on the Lacey's are genetically determined. There is currently research happening right now that is looking into the genetic causes of white spotting. Though the way things are coming out, it is more difficult than originally postulated. The gene causing piebald white has been discovered, but the same gene does not seem to fit all spotting patterns seen in all breeds. I am not at liberty to share more than that as research is still ongoing.

The developmental white spotting does not extend to the degree that is expected on the Lacey's. It is usually just an inch or two in length and quite narrow. There may be a toe or two on a couple of feet that are white, but never a whole foot. Once the white gets that large, I would consider it to be genetic.
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Sadie

Sassy and Shady		 
 
Barked: Mon Aug 4, '08 1:55pm PST 
Gio, I figured it had to be genetic on most dogs. But on some, like mine, it seems to be more of the developmental variety. Sadie has a few white toes and about 1" of white on her chest. Her liter mates had minimal white as well.

I'll be very interested to know how the studies turn out. Right now the best breeders use "cowboy genetics" to keep white out of their lines. If they see a dog anywhere on the papers that has been known to throw white, even if the dog they want to breed has minimal markings, they won't mix with that line. Unfortunately there are some breeders that are more interested in perpetuating the blue coloring and don't care if their stud or bitch produces excessive white as long as the original dog is standard. Do you have any insights on a more scientific approach to keeping white to a minimum, or is the rancher's philosophy of never mixing in a line that has had excessive white enough?
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Gio

CD RE (CKC) RACL- (CARO) FM CGN- SJATD HIC
 
 
Barked: Mon Aug 4, '08 5:48pm PST 
There is one recent publication on the gene behind piebald white. I have the paper at work so will post a reference here tomorrow when I am back at the office.

What sort of white are the Lacey breeders trying to avoid? Do they want chest/foot white? Are they avoiding whole-body (piebald) white or just anything more than a chest spot?
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Sadie

Sassy and Shady		 
 
Barked: Mon Aug 4, '08 7:13pm PST 
Gio, any real scientific reference would be great.

Lacy breeders are trying to avoid anything more than white on the chest, stomach and paws. But they are supposed to have at least a little white on the chest and on at least one paw. I've never seen a Lacy come out truly piebald like a BC or something, but I have seen it on the face and tip of the tail which are considered disqualifying faults. At the same time, they want some white, so I'm not sure how you balance it out.

There is a belief that excessive white means some sort of other breed had to be mixed in at some point. I don't know a lot about genetics, but it seems like it is probably just a mutation. But what is the best way to track that sort of mutation in a line?
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Gio

CD RE (CKC) RACL- (CARO) FM CGN- SJATD HIC
 
 
Barked: Mon Aug 4, '08 8:05pm PST 
The recent reference that I have does not explain the sort of white that you are talking about.

As far as I know, the mutation in the paper results in piebald and extreme white. Border Collie white, also called "tuxedo" or "irish" spotting is not the same thing as piebald or extreme white. I personally believe that is controlled by another gene all together, though it has yet to be proven through molecular genetics. I also believe that facial white is another gene not related to piebald/extreme white or irish spotting.

The white that you describe Lacey's as having, IMO, is the same thing as "irish" spotting, just possibly altered by a promoter mutation or something that affects its penetrance, or the extent to which it is expressed. ie. full border collie white collar compared to a white chest. Same "marking" just one extends around the neck and the other stops short.

Looking at breeds that have this variation in pattern, it appears as if full white markings is recessive to "minimal white", like in Lacey's. I've seen matings of Shelties, sire with a full white collar, dam with minimal white, all pups have minimal white. Same full collared sire bred to another minimal white dam and all pups have minimal white. So looks recessive to me.

A good way to avoid full irish markings would be to not breed to a line that has an irish marked dog in its pedigree, at least for 4-5 generations anyways. With the well-being of the breed at hand, breeders may want to take the "risk" of breeding to a line with white, just selling the mis-marked pups as pet quality. Irish spotting is definitely not an indicator that there has been cross-breeding, if the phenotype existed in the breed in the recent past, then it could just be "lurking" unexpressed. Though crossbreeding could definitely cause the same result, it is not a guarantee that there has been crossbreeding, and excluding whole lines because there has been a spotted dog or two produced would be committing breed suicide. Management of rare breeds cannot be maintained through yes or no exclusion from breeding. Weigh the risks for the benefit of the breed.
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Sadie

Sassy and Shady		 
 
Barked: Wed Aug 6, '08 11:39am PST 
Thank you for all the info, your explanation of the markings was extremely helpful!

So essentially the excessive white would have to be present in both the dam and the sire (or in both the lineage) to express itself in the pups, correct?

We've also noticed that excessive white on the face seems to appear with a white tip on the tail and/or excessive white on the legs. The chest doesn't seem to be as connected. Does that still make sense given the recessive nature of full vs. partial Irish markings?
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Gio

CD RE (CKC) RACL- (CARO) FM CGN- SJATD HIC
 
 
Barked: Wed Aug 6, '08 1:35pm PST 
I think that is how it works. It appears to work that way anyways. But don't quote me on it as the actual research hasn't been done yet. It is just what I have observed from various segregating families.

If you talk to breeders of breeds like Shelties, Collies, Border Collies, etc. that commonly have the irish markings, they will tell you that you can tell a "white factored" dog just by looking at it. Or, in other words, a dog that carries the recessive piebald allele. If a dog has a larger amount of white on the tip of its tail and has white extending over the "knee" on the hind leg, then it likely carries the recessive piebald allele. This of course isn't proven yet (I hope to do some side research when I get the chance and run a few of these sorts of dogs to determine for sure). As for the full versus partial irish spotting pattern, I'm not sure if there are any known "signs" that a dog carries the full irish allele. I would guess that more white on the tail and up the legs might indicate that they carry the full irish allele. But that is just a guess.

I have tested both of my dogs (Gio and Romeo) and neither of them carry the recessive piebald allele. But Romeo has full white up both front legs connected to the collar, while Gio has white only part way up his front legs and an "incomplete" collar. This may be a clue as to how the irish spotting alleles differentiate. No idea as of yet!

As for facial markings, I'm not convinced that they are connected in any way to body spotting. In my mind, I still believe that facial spotting is completely separate from white body spotting. But I have no proof to back that up.
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Buddy ☮

Ducks Are My- Nemeses
 
 
Barked: Fri Aug 29, '08 10:11am PST 
I don't have anything to add but I have been reading through through the threads in this group and it has been so interesting! Thank you for the great questions and answers pups!
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