I have been reading as much as possible about genetics and the
results when you mate different coloured labs.  However, I am
aware that you can have a dominant black lab that carries no
yellow or chocolate, or a lab that does carry the other colours.

Is there a way to determine, before breeding, which genes your
lab carries?  Both my labs are black, bred from a black mother
(who has chocolate further back) and a yellow father.  Upon
looking closely at my dogs there is a definate difference in
coat colour - one is black with brown undertones and the other
is purely black with no hint of any undertones.  Does this help
in determining their dominant colours at all?

Any advice would be greatly appreciated.

On the face of it your dogs could carry the genes for all three colours. If mated to a black without the recessive yellow or Chocolate then the puppy's would all be black. (Black is dominant in Labradors) Mated to a Black containing either of the other colours there would be three quarters of the puppy's black and a quarter coloured.

Of course, just because there are the other colours at the back of your dogs does not mean that your dogs have inherited these genes. The only colour you can be sure of without testing is black. To check for other colours there is a DNA test available.

Regards, John

Thanks for the advide - I wasn't aware that you could do a dna test which will tell you the colour genes, do you know where this is available or will my vet do it?

Cheers

If your black dogs have a yellow sire then they will definitely carry yellow.

Thanks again for the help.

Maybe I am being a bit dim but I thought that although my dogs sire is yellow and the majority of pups will carry yellow - that they can still produce a completely dominant black pup although there is a small percentage of that happening?

The same would ring true as in my case, ie, black haired parents, all offspring bar me with black hair - I'm redheaded.  And before anyone says it, they are my parents!! Turns out great grandparents on both sides were red.

I probably need to do a lot more reading on the subject!

If black is dominant to yellow, a yellow cannot be carrying black, and therefore can't pass it on.

   Crusty roll
                       "I thought that although my dogs sire is yellow and the majority of pups will carry yellow - that they can still produce a completely dominant black pup although there is a small percentage of that happening?  your dog could only produce a dominant black pup if mated to dominant black Dog not another black carrying yellow .

   Hope this helps and dosent confuse

  Yorker

Are you sure, yorker? If a black dog was sired by a yellow dog (bb) out of a black bitch (BB - 'pure' black; or Bb - black carrying yellow), then the pup will be Bb. If mated to another BB black, then half the pups would (if I understand it correctly!) be BB and the other half Bb; ie all black. If mated to a Bb (black carryin yellow) theoretically there would be a quarter of the litter BB ('pure black'), half Bb (black carrying yellow), and the final quarter bb (yellow).

    Jeangenie
                       i am no expert but thought i understood how it works ? in the book Dual purpose labrador is the following explanation based on a litter of 8 puppies .
   BB x BB = 8BB pups
   BB xBb  = 4BB Bb pups
   BB x Y  = 8bb pups
   Bb x Bb = 2BB 4Bb 2Y  ( someone told me this was incorrect it should be 6bb 2y )
   Bb x Y  =4Bb 2Y pups
   Y x Y = 8y pups

     Mary Roslyn williams also states breeding chocolate labradors  upsets the whole apple cart 

I'm a little confused by the abbreviations you use, yorker. The first two exmaples are fine, and absolutely what I'd expect, but why does the Yellow in the third example not have two genes? Are you using bb to show yellow (as I did)?

In that case the third example would be BB x bb; which cannot give 8 bb pups, because the dominant BB has not contributed any genes at all. Your fourth is what I would expect with the two BB/4 Bb/2 bb (yellow); the fifth is only giving 6 pups - I would expect 4 Bb, 4bb (yellow), and the last is what I would expect also.
:)

   Jeangenie
                    i am getting a little out of my  depth i took BB to mean Dominant Black Bb to mean Black carrying the yellow gene Y to mean Yellow  i agree with you regarding the fith one being 4 black carrying yellow and 4 yellow

   Sorry for the confusion Yorker

So in the third example there would be 8 Bb pups, ie all 'black-carrying-yellow' (with the lower-case 'b' representing the yellow gene). Yep, that seems right to me.

It all gets so confusing doesn't it? 

I've just gone over the genetics site (link from Kennel Club -
http://www.doggenetichealth.org) and using all the combinations that my black bitch could be, and all the combinations that the potential yellow stud could be, it turns out we could have:-  a litter of all black pups, a litter with yellow and black, a litter with black and chocolate and a litter with all three colours!!

I had also been told that if you mate two black dogs, all you will get is black, but the website shows that you can have yellow pups from two black dogs.

I did have a look at the other link supplied and it was helpful as well.  I think it is just going to take time for me to absorb all the information!

If the relationship between black and yellow in labs is the same as black and liver in dalmatians (ie, black is always dominant to liver), if you mate two blacks who are both carrying the gene for the recesive colour then yes, two blacks can indeed produce a proportion of yellow (or liver in my case) pups.

Hi Crustyroll

The confusion seems to be because there are two loci (genes sites) involved in the three colours.  To be black the genotype must be B_  E_.  B is for dominant black and E for full extension of dark pigment.  Bb Ee is a black dog carrying chocolate and yellow.  If a dog is ee it will be yellow whether it is BB or bb as the ee recessive combination is epistatic (overides) black or chocolate.

If your black dog has a yellow parent he will be BB Ee or Bb Ee.

BB EE  - black
Bb EE  - black carrying chocolate
BB Ee  - black carrying yellow
bb EE  - chocolate
bb Ee  - chocolate carrying yellow
BB ee  - yellow "carrying" black
Bb ee  - yellow "carrying"  black and chocolate
bb ee  - yellow "carrying" chocolate

Two blacks could produce any colour depending on the recessives carried, including the rarer Lab colours...brindle, tanpoint, sable etc

Hope this helps and hasn't added to the confusion :-)

Julie

There are a number of companies doing coat colour prediction, although because of companies taking out patents on large sections of DNA most are in the USA. Have a look at:-

http://www.vetgen.com/color.html

I have no personal knowlege of this because I've never used the service but I know some people on this board have used DNA tests for coat.

Regards, John

Thanks John,

The reason I am going to so much bother about this is, having read some web pages with stud dogs advertised and claims that they only carry 'black', 'yellow', 'chocolate' etc it makes me question, does the breeder really know?  Have they had the test or purely by breeding they know?  I suppose the simple answer would be to ask the breeder but I would really like to know what my own dogs carry.

Cheers

The short answer is, you can never be sure without DNA testing. Take my Anna for example:-

My Beth was a yellow out of a Chocolate dam. Her sire was Heatherborne Statesman. Therefore Statesman must have carried the Chocolate and Yellow gene.

Anna is yellow out of a yellow bitch by a Black dog. The yellow bitch Great grandsire was Heatherborne Statesman.

From that it follows that Anna COULD carry all three sets of genes but does she? A puppy inherits a set of genes from both sire and dam. A dominant on both sides is dominant. (2 blacks = black) A recessive on each side becomes the dominant (Yellow to yellow = yellow). At any mating a set of genes is lost so it follows that a gene for a colour can disappear from the genome at any subsequent litter.

Look at hereditary complaints, Cataracts in Labradors for example, a straight recessive complaint. Mate a dog with cataracts to a bitch with cataracts and the pups will have cataracts. Mate a carrier to a carrier and half the puppies will develop and half will be carriers. Mate carrier to clear and NONE will develop, half will carry and half will be completely clear! The trick of course is knowing for sure which half!!!

All this is possibly over simplified because I'm not a geneticist. Just a layman looking in the door.

Regards, John

Just read through the rest of your post John -

"Look at hereditary complaints, Cataracts in Labradors for example, a straight recessive complaint. Mate a dog with cataracts to a bitch with cataracts and the pups will have cataracts. Mate a carrier to a carrier and half the puppies will develop and half will be carriers. "

It's possible that half will be carriers and half affected but the expected ratio over a large sample of carrier x carrier matings is  - 25% clear 50% carrier 25% affected

Julie

Here you have "an illustrated guide" to lab coat colour inheritance including a link to a DNA test:  
http://members.ozemail.com.au/~gentest/color.html

John wrote -

"My Beth was a yellow out of a Chocolate dam. Her sire was Heatherborne Statesman. Therefore Statesman must have carried the Chocolate and Yellow gene.

Anna is yellow out of a yellow bitch by a Black dog. The yellow bitch Great grandsire was Heatherborne Statesman. "

Unless Stateman has actually produced chocolate or is gene tested to prove it, there is no way or knowing if he carries it.....the only priviso being that his yellow dam and all of his yellow progeny also have black pigment (or at least did as puppies).  Yellow and chocolate are different genes and producing yellow is no indication of chocolate.  Statesman is either BB Ee (carries yellow not chocolate) or Bb Ee (carries chocolate and yellow).

Julie

Sorry Julie, I forgot to add that Beth's litter also contained some Chocolate puppies so Statesman MUST have contained the choc gene.

In your other post, yes, I'm wrong. both the sire and dam would contain one clear gene and one affected gene so yes, all three states could occure.

Regards, John