Who carries the ee gene?

Discussion in 'General breed discussions & FAQ' started by clucknpeck, Feb 3, 2013.

  1. clucknpeck

    clucknpeck Chillin' With My Peeps

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    Hi everyone, I would like to talk genetics a bit.
    Here's my questions- does the hen or the rooster carry the easter egger gene?
    Can you make second generation Easter eggers if the rooster has the white egg gene?
    If you breed an ee rooster to a brown layer will you get an olive egger?
    And lastly, if you breed an ee to an ee, but these ee's lay tan eggs, can their offspring lay colorful eggs?

    I am ready to be informed!
     
  2. Ridgerunner

    Ridgerunner True BYC Addict

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    There is one gene that determines the base color of the egg shell. That base color is either blue or not-blue. Not-blue defaults to white. There are several genes that affect brown. That’s why you can get so many different shades of brown or green. Shade of brown or green depends on which of the brown genes are present. Green is just brown on top of blue. Think of it this way.

    Base blue + no brown = blue
    Base blue + brown = green
    Base white + no brown = white
    Base white + brown = brown

    All chickens carry two copies of the blue or white gene, male or female does not matter. The blue gene is dominant so if the hen has just one copy of the blue gene, her eggs will be base blue. You just won’t know if she has two copies of blue, which is called pure for that gene, or one blue and one white, which is called split. Roosters don’t lay eggs so with EE’s you don’t always know if they have the blue egg gene or not.

    If your hen is laying white or brown eggs, she does not have a copy of that blue egg gene and cannot give the blue egg gene to her offspring. If she is laying blue or green eggs, she has either one or two copies. You cannot tell which by looking. If she has two copies she will give one to all her offspring so all her daughters will lay blue or green eggs regardless of what the father gives. If she is split, some of her offspring will get the blue egg gene and some will not.

    Same with the father, except he does not lay eggs so you cannot be sure what he has. If he does not have the blue egg gene he obviously cannot give it to any offspring. If he is pure for it, he will give a copy to all his offspring. If he is split, some will get it and some won’t.


    In answer to one of your questions, will a brown egg layer mated with a chicken that has the blue egg gene make an olive egger? It depends on what brown is inherited. If it is a light brown it could be a mint green, not a deep olive color, assuming the blue egg gene also shows up. I think you can figure out the answer to your outer questions if you read this closely.
     
  3. clucknpeck

    clucknpeck Chillin' With My Peeps

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    Thank you so much! This answers my questions completely.
     
  4. draye

    draye Overrun With Chickens

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    Ridgerunner you explain things so well.

    So if I am understanding right with my Polish/EE cross hen, she lays a green egg.
    This means that her mother should have had 2 copies of the blue egg gene, but since her dad was from white eggs (Polish), then she will only carry one copy of the blue egg gene.

    So, if I breed her to the blue egg gene (Ameruacana) then her daughters should get 2 copies of t he blue egg gene. If to a rooster that came from a blue egg but a dad that came from white egg (Polish), then daughters sould receieve 1 copy of each. If to a rooster that came from a white egg (back to Polish) then most likely will lay a white egg.

    Did I get this right?
     
  5. Ridgerunner

    Ridgerunner True BYC Addict

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    This does not mean her mother had two copies of the blue egg gene. Since blue is dominant, she only needs one blue gene to lay a green egg. But that does not matter. If your Polish/EE cross is laying a green egg, she inherited the blue one from her mother. Since her father came from a white egg, your basic assumption is right. Your cross has one white gene and one blue gene.

    Since she is laying a green egg, brown is in the mix so the odds are tremendous all the eggs with the blue gene will be green even if you cross her with a rooster from a white egg breed. So I’ll use green for egg color in your case.

    It may help to think about it with symbols. Some people understand it better that way. Use uppercase “O” for the dominant blue gene and lowercase “o” for the recessive white gene. Your split hen would be O,o

    If you breed your cross to a rooster that has two copies of the blue egg gene, about half the offspring will get two copies of the blue egg gene and about half will get one blue and one white. All the daughters will lay a green egg but you won’t know which have two copies of the blue gene or which are split blue/white.

    The rooster would be O,O. When you cross chickens they give one of the two genes they have at that point on the chromosome to their offspring, but which one is purely random. If you cross the O,o hen with the O,O rooster, all the offspring will get an O from the rooster but half will get an O from the hen and half will get an o. So about half the offspring will be O,O and half will be O,o.

    I think it’s worth saying that this is random whether the hen gave an O or an o to each chick. When I say half or ¼ that is just the odds. It’s very possible if you hatch out 4 chicks, all 4 will get the O or all four might get the o. You just don’t know. You have to hatch a lot of chicks for the odds to mean anything and they really don’t mean anything with an individual chick.

    If you cross her to a rooster that has one blue and one white, about ¼ of their offspring will be pure for the blue egg gene, about ½ will be split blue/white and still lay a green egg (at least the pullets. I know roosters don’t lay eggs), and about ¼ will not have any blue egg genes so will lay brown eggs.

    In this case the rooster and hen would both be O,o. Each will give about half their offspring an O and half on o. About half the chicks that got an O from their father will get an O from their mother and be O,O. Half will get an o and be O,o. Half the chicks that got and o from the rooster will get an O from the hen and be O,o. Half will get an o and be o,o.

    When you do the math, ¼ are O,O, half are O,o, and ¼ are o,o.

    The last cross is the hen O,o and the rooster o,o or a white or brown egg. Half will be O,o and half will be o,o.

    Remember that as long as one O is present, the hen will lay a green egg.
     
  6. draye

    draye Overrun With Chickens

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    I'll have to read two or three times to get the full meaning.
    I thin kI understand, just will read again to make sure.

    Thanks.
     
  7. clucknpeck

    clucknpeck Chillin' With My Peeps

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    I have one more question for you ridge runner, you said you can't tell by the egg who has the dour blue gene. Does this also apply to bird breeds that always lay true blue when pure, like a cream leg bar?
     
  8. Ridgerunner

    Ridgerunner True BYC Addict

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    I sure can't tell by looking. Chicken genes can be tricky with some partially domimant, some incomplete dominant, and some just plain dominant. The way I understand it the blue egg shell gene is totally completely dominant so if just one copy is there it will look exactly the same as if two copies are there. From looking at my blue and green eggs, it sure looks like it to me.

    Some genes don't work that way. If you have a rooster with two barred genes, it will look lighter than a rooster with one barred gene, though both will be barred. Or as I recently learned, a chikcen with two crest genes will have a bigger crest than one that just has one crest gene, though both will still have a crest. Barred and crest are both dominant, but not totally blatantly unashamedly dominant like the blue egg shell gene.
     

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