If it's rare to get black puppies from chocolate to chocolate, what color are the puppies from pure chocolate to pure yellow?

All black.And they will all be Byc.

More trolls. I'm sure you already know the answer. However, since you asked, it is the combination of the B (for black pigment)allele from the yellow (eeBB) combined with the E allele (for dark coat). In layman's terms, when a dog inherits the dominant allele E (for dark coat/black coat) along with the dominant B allele for black pigment, you will have all black puppies because both dominant alleles are present.

It would look like this: (remember each pup inherits one copy of the coat/pigment allele from it's parent.

Pure for chocolaote (EEbb)
Pure for yellow (eeBB)

Resulting pups, black=EeBb

So if you bred two chocolates, neither one could ever carry the B allele that would be necessary for the black expression or they themselves would be black. As some self appointed expert has been toting about a possible mutation of the genes that can "allegedly" produce a black pup, you would still need the B allele for black pigment. Chocolates are simply EEbb or Eebb. It's not just rare or happens on occasion, producing a dominant color from two recessive colors are about the same odds as being struck by lightning. I mean seriously, what are the odds of a spontaneous gene mutation?

Waiting for the expert to jump on me again to call me ignorant................

You were the one to accuse others of being ignorant in the first place. Perhaps that is not the right description for your mindset. It is more like the base term - ignore: Refuse to take notice of or acknowledge; disregard intentionally. With a closed mind, it is inevitable to be ignorant of new research.

For the OP, your question was answered very simply by the first post. I have done this type of mating several times and appreciated that my black pups carried both recessives so that I had more choice in what colors I might select for in the next generation

I just reviewed the chocXchoc thread and realized you were not the one to start calling names. It was someone posting as "Just Me Too Wow!Wow!" You then bought into it in your posts. I am not ignorant of the facts nor do I ignore new research when it is published. For many years I would have told people the same thing you did. The difference is tht I didn't stop learning once I had a basic grasp of the genetics of color.

When the first litter of my personal experience with a black pup from chocolate parents happened, I recommended parentage testing for all the same reasons you would. The DNA results indicated that the black pup WAS from those two parents. It made me go do some more in-depth research. I found parts of the answer in several different articles published in genetic journals. When the second litter with 2 black pups from chocolate parents came to my attention, I again recommended DNA testing. The proof of parentage again showed the black pups to be from the chocolate parents. By this time, I had talked to enough researchers and read enough literature on the topic that I could accept the science for this very rare occurrence.

The message here is that even the experts keep learning and exploring - that is part of what makes them experts. Once you assume that you know everything about any topic, your information is doomed to become outdated. Stay open to possibilities and if your "old" reliable thinking does not explain what you observe, go back to the drawing board. Our means of investigating the canine genome and the huge range of ongoing research expand every year. Keeping up with all the new discoveries is nearly impossible. Absorbing ANY of them is impossible if you are convinced you already know it all.

something this rare and unusual should be written up - have you thought about publishing an article? what have the geneticists said about this? does the pup have black or chocolate pigment? have you run a color test to see how it has come back, just for curiosity sake? what explanations did you get about this?

Yes, this is very intriguing. What did the science indicate in the appearance of these blacks from chocolate parents? How was it determined that it happened?

Look at the email addy. The poster is tbirdlab, who on more than one occasion has caused arguments on this forum with his silver lab agenda. My suggestion is not to get caught up in his nonsense. You cannot educate people who own and breed "silvers" as they just do not want to hear it.

A few answers. The blacks from two chocolates were typical blacks. One of them is a champion The genetic test for the various TYRP1 mutations show that these black dogs have TWO mutations for brown/chocolate. This is what you would expect for a chocolate dog. However, the way the mutations crossed over and aligned at the time the gamete formed allowed these to be combined in "one" of the gene pairs and the other member of the pair defaulted to black. That is, the gene sequence for that half of the pair did not have any of the TYRP1 mutations that cause brown/chocolate. So, the dog would be represented using simple notation as BbEE. The "b" portion, however, has two different mutations for brown/chocolate in the sequence - one from each parent. As I said, it is complex and rare.

I don't pretend to really understand all of the implications, but I did bother to read the research when what I observed in real life did not match what I had previously learned from the "Little" book on canine coat color. The information is out there - you just have to WANT to look for it. The greatest obstacle to knowledge is complacency.

Thanks for the follow up information. It is much appreciated. This is fascinating indeed. Did the Bb(b)EE Black then go on to produce black and chocolate puppies in the Mendelian expected proportions when bred?

Yes, "Chocolate Breeder" I am a proponent of Labradors that carry the dilution gene aka "Silver." That is no secret. If I wanted to hide that, I would have dropped the "simple" moniker and not posted my email... I did not bring Silver up here in this thread, nor did I in the "Chocolate to Chocolate" thread, you did, both times. If you want to talk Silvers and trash their breeders as you have endeavored to do in your recent posts, feel free to email, I'd be open to discussing it with you or anyone. If you prefer not to talk, you can search out the old threads and reread them. If I have "caused arguments" here in the past, it is simply because I gave a voice to Silver Labs and their breeders amidst a chorus of those here who like to pile it on. Point, counterpoint, makes for fair, if not entertaining discussion.
How about we keep this and the other color breeding thread on topic shall we, Blacks from Chocolate parents; no need to drag dilution into this...is there?

Thank you again "Just Me Too" for providing more information.

Because of your belief and breeding in *silver dilution* and repeated arguments on here, anything you say is difficult to believe. I haven't read your posts since I saw your email address. Once you've lied, you'll never be believed. Not by Labrador breeders that know much more than you could ever learn.

Just sayin'................

BTW, I have heard for sure that pure for Chocolate bred to pure for Yellow *can* produce heavier coats in those black puppies. Take that one in your pipe, and smoke it. Alot you don't know about that others do. You're too busy trying to create Silvers to keep learning. You don't care about a double coat, you care about the color of it, nice n slick.

Wow, really, nice to meet you too. You talk like you assume you know me when in fact you actually don't; you would have never said those things if you did as they are categorically incorrect.

Please direct me to any post here where I ever lied. If I did, I will publicly retract.
If you are just bored and want to fight it out over silvers, please email, I'll oblige. No sense in doing here, we've all been there done that.

Shall we return to the topic? I would love to hear more about these surprise blacks from chocolate to chocolate breedings. From the comments of others here I think they would too, especially since we have an individual nice enough to share their personal experience and first hand research into a phenomenon that is evidently very very rare.

it is common knowledge that the pure chocolate to pure yellow will throw blacks. Most breeders will agree this is the only time chocolate should go to yellow.

I have been breeding chocolates for 25 years and in labs for 30 yrs. I have seen many mis marks but never seen a black puppy out of two chocolates. I would need to see proof before I would accept this as fact.

This is one of the reasons "freak shows" were so popular in the age before the internet. Some people simply can not believe what they don't PERSONALLY see with their own eyes

I have never personally seen a litter with a long-coat Lab. I have never seen a pup born with an extra or missing limb (or portion). I have not seen LOTS of anomalies that occur in dogs, but that doesn't make them untrue. I have also never been to the moon, but believe the astronaut who told me about his moon walk. If I had to rely on only first-hand eperience to absorb knowledge, I would not know very much and also seriously limit my ability to understand what I do experience.

Maybe "most" breeders agreed with you 20 years ago But now we have something called coat color test. Its very simple actually, just a cheek swab. Today, a breeder can make an educated decision and breed a Yc to a Cc and get a black and chocolate litter. A breeder can choose to breed a Cy to Y and get a black and yellow litter. To even go off topic, a breeder can breed a Yc to a Byc and get black, yellow, chocolate and a 12.5% chance of a NBP yellow. 12.5% is not the end of the world for me (and I will not speak for most breeders today).

Making a statement that "most breeders agree" is simply incorrect in this day and age.

I agree with this. Most breeders do not agree about that anymore. In fact, most breeders years ago would not even cross over their yellow and chocolate lines at all. But now we can! I personally will avoid breeding 2 labs that BOTH carry yellow AND chocolate. I prefer not to produce any NBP pups. But other than that, let the fun begin!

I don't breed chocolates, so I haven't studied this topic myself. I have been reading between the lines to interpret what you are saying. Tell me if I am correct. You are calling the gene that is mutated to cause the chocolate color TYRP1, so I assume it encodes an enzyme in the pathway that leads to melanin from tyrosine. Again, tell me if I am correct. All chocolate labs would have two mutated TRYP1 genes, but the muttons inherited from two chocolate parents may not be the same mutation. If a crossover occurs between the two mutations (this would indeed be extremely rare) you could get a dog with a functional gene and enzyme from two chocolate parents and that dog would be black. This makes sense genetically. Is that indeed the case? Are there multiple mutations within the chocolate gene in our Labrador gene pool? What does this say about the origins of the chocolate color? Does it have multiple sources?

Yes. There are three different ones commonly found in Labradors. There is a fourth that has been identified in some breeds, but testing in Labs has not been published. Read that as it might be present, but I have no evidence of it from published sources
Your other comments are right on track. This was not an easy subject to research and evaulate. What I knew was that the phenomenon happens in real life and there had to be a scientific reason for it. Many thanks to the various researchers who did the gene studies and several who took the time to explain how the different mutations can align to give the occasional black from chocolate parents.

Thank you. I think this would be the only way this could occur because the chocolate color is caused by loss of function of the TRYP1 gene. It would be highly unlikely to get a gain of function back mutation in any other way.

Yes, but I have seen photos of long coated labs and can easily find the reputable breeder who was honest enough to share, and I have seen photos on other reputable breeders sites showing deforminities and missing limbs. I don't have to see it with my own eyes to believe because I believe the source. When you provide such credible evidence like photos, pedigree, or even a link to the journal that reported that these mutations can happen and create black out of 2 brown parents, THEN I will believe.

And I have seen black pups from two chocolate parents with DNA proof of parentage. With my own eyes. Below is a link to one of the research articles on brown coat color explaining the various mutations. The other two reports I read are not available online. Enjoy the light reading
http://www.springerlink.com/content/72vj9fr4nwc362e6/fulltext.pdf

Thanks for the link, a good read.
For clarification, was the Black(s) from the two Chocolates the result of a pairing between two TYRP1 mutant heterozygotes (like bS and bc and/or bd), ultimately making the dog a bb Black? The way I first understood what you posted previously was that two heterozygous b mutants (like bS and bc) had combined into one single novel bmutant allele, the other allele being a void then defaulted to B. Was the Black Lab DNA verified as Bb or bb? I guess that would best answer it.
Also, what were the offspring colors from these Blacks, did they appear as expected under Mendelian probabilities?

Yes. This is the case. The two specific mutations that have to be present to do this crossover are S41C and 345delP - one from each parent. The stop codon (Q331ter) will not combine and will always take one gene pair by itself. The S41C and 345delP have some kind of heirarchy arrangement where they can "share" one gene pair. In this specific case, the dog will be have two mutations for brown, but will be black (BbEE). Of course, this does not reflect what happens when you confuse the whole issue with yellow!

The DNA gene testing can only test for the presence of the mutations. The fact that the dog has two brown mutations would usually mean the dog is phenotypically brown. However, all the companies that do gene testing ask for the color of the dog on the application, which is what brought this anomaly to the attention of Randy Smith at DDC some time back. Dogs that tested to have two mutations were outwardly black. His research and mine led to a viable explanation for the odd finding.

That's more than simply fascinating, it's awesome!

This level of genetic understanding is so liberating! The ability to concisely explain how such an occurrence actually happens, at the molecular level, is awesome!
I can't wait until they figure out the DNA for the color variation we see in yellows.

Thanks for sharing Just Me Too.

Just saw your second part here. So Black Labs tested as bb? Wouldn't that support the first of my deductions, the bb mutant over the Bb mutant?

No, it isn't that simple. When you use notation like "bb", you are describing the gene pair. The black dogs that have two chocolate mutations have BOTH mutations on just one of the pair. If you tried to use common notation, it might look a bit like "B(bb)" or some other strange configuration. There ARE two mutations, but they are both in ONE of the gene pair. As to what they produce, nobody that I know has followed their production to see if they have a statistically higher probability for producing chocolate. It would logically seem so, but it might not actually happen in real life.

Thanks for the follow up, I wanted to be sure I had understood it correctly, I had previously used the notation as Bb(b)EE, but BbbEE would let one know that something is up with the b just as well. I guess the proper notation would be close to BbSbdEE. I am sure actual nomenclature is much more involved including the sequence variants.
It would be interesting to see how the mutated bsbd was passed on at the molecular level and if/how phenotype is subsequently influenced

I hate to nit pick, but the "bs" is not one of the mutations in this phenomenon. That represents the stop codon, which is the most common brown mutation. It never combines and claims one of the gene pair when it is present. The two that can combine are the prolene deletion (bd) and the cystine substitution (bc). You have the right idea, just the wrong mutation

Pay attention! Nobody said anything about the D locus. The bd notation was being used to indicate the TYRP1 mutation as a result of a prolene deletion at residue 345. You have to follow the whole discussion and read the actual research paper or you won't know what we are talking about. You are so single-minded about slamming silvers that you can't be bothered to actually try to understand what is being discussed. Get off your soap box and you might learn something!

Pardon my rant, but I really run out of patience with people who aren't interested enough to even try to learn something new to them, but want to promote some private agenda.

I'm finding you very interesting and well educated in genetics Just Me Too. I'm enjoying what you have to say. Finally someone that knows alot more than tbird *thinks he does* and is showing their intelligence. I hope you're at a level of teaching, your damn good at getting the point across properly and intelectually. Thanks for giving all of us *real* Lab Breeders a good genetics lesson. If you're in the US, Happy Thanksgiving. I do know it's on Thursday but I start cooking tomorrow and won't be around for 2 days to watch this discussion. YOur miles ahead of tbird and I'm glad you know it.

No problem on the nit pick. I had switched Q331ter for S41C. Thanks for keeping it straight, the correction is appreciated. So we are looking at a notation of BbcbdEE.

For "You're Interesting," I never once suggested I knew more than "Just Me Too" on this topic. If you look back, I have been most intrigued by this discussion, particularly since "Just Me Too" has actual first hand experience and original research into the subject. Yes, I have learned from "Just Me Too," I would hope that this discussion has helped other breeders here learn as well. Perhaps now folks wont be jumping to the quick, easy, and pretty much thoughtless conclusion when a Black is produced from Chocolate parents and mismating is not likely. DNA test then seek for understanding.
If anyone wants to rag on my knowledge of genetics, feel free...but I didn't notice too many, other than Peggy, actually contribute to this discussion...guessing Schmutz et al. threw some for a total loop.

I guess I missed the part where this was about some kind of contest between myself and "Just Me Too." Certainly not the way I ever saw it. I give props to "Just Me Too" for your willingness to openly discuss this topic when you had would-be peers criticizing and doubting you. I, for one, have taken this opportunity to strengthen my knowledge of canine genetics today and look forward to similar future opportunities.

Gee, I always though if you bred a choc & yellow you would get dudley pups......so much for what I thought I knew.

Dian has an awesome resource available, check it out!

http://www.blueknightlabs.com/color/coatcolor.html

That is the old way of thinking. The only way to get a dudley or a NBP pup is if BOTH parents carry yellow AND chocolate. For instance, a Byc to a Yc, or a Cy to a Yc, or a Byc to a Byc....etc.

What you don't want is a eebb. If pigmentation on an eeBb is not fine, it is for other reasons. So you can breed yellows to chocolates as long as the chocolates don't carry yellow, or the yellow doesn't carry chocolate. You also wouldn't want to breed two yellows together who both carry chocolate, or 2 chocolates together who both carry yellow.

If the worst problem you ever get from breeding is a bbee, that is one more thing to be thankful for on this special day

Finally someone who understands

I dont doubt the presence of mutations, however the probability of the same highly infrequent mutation occurring in two puppies in the is astronomically low.

Am I to understand that AKC ran DNA paternityy on both pups and DDC concluded this mutation had occurred in both as welll?

When a dog inherits the particular two mutations for brown that are noted above, the dog will be BLACK, even though it has two mutations for brown. It is just the way those two specific mutations align to ONE of the gene pair. It will not always be from two brown parents, but it can be.