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gentetics question, does half plus half make 1?

Discussion in 'General breed discussions & FAQ' started by chicken burger, Jan 25, 2011.

  1. chicken burger

    chicken burger Chillin' With My Peeps

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    Here's something I've been wondering. I have a dutch cross OEG bantam rooster and hen. These chickens have white ears like the dutch but yellow/pink legs like the OEG. They have recently had another batch of chicks .. Out of the 6 chicks, one chick has slate legs like the dutch are supposed to have. It turned out to be pullet. My question is...will I be able to get a pure bred dutch eventually if I breed the father to the daughter again?
     
  2. karimw

    karimw Chillin' With My Peeps

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    Alas no. The number of genes involved will always give you a chance of getting something non standard down the road. You may be able to keep certain traits common, but not 100%. The unfortunate part of close inbreeding is you may also concentrate unwanted and unhealthy genes.
     
  3. FireTigeris

    FireTigeris Tyger! Tyger! burning bright

    I plucked this from another thread:

    Quote:http://i9.photobucket.com/albums/a83/PiAmoun/Gallusinae/OnagadoriShiki.jpg
    Tosa Onagadori
    For example, Japanese researchers in Hawaii experimented with the most parsimonious method to reach the Onagadori stage of the long tailed cultural treasure. Following Japanese tradition, they utilized a specific form of backcrossing- more specifically, matrilineal backcrossing- that is, male progenitor to matriarch over successive generations.
    http://i9.photobucket.com/albums/a83/PiAmoun/Gallusinae/Kawachi-Yakko.jpg
    http://i9.photobucket.com/albums/a83/PiAmoun/Gallusinae/Tosa-Kojidori.jpg
    First, an appropriate female was selected. She was from a very homogenous Tosa-Kojidori X Tosa Mikawa strain. This is the Japanese equivalent of a Leghorn cross battery egg producer. Neither of light weight egg producing progenitor breeds, the Kojidori or Mikawa are long tailed breeds. The researchers chose the egg producer because the genome of the strain was completely mapped and the strain is closely bred to the point that each egg is produced by each hen is nearly identical in size, weight and shape.
    http://i9.photobucket.com/albums/a83/PiAmoun/Gallusinae/Tomuhen.jpg
    The " Tosa Tomu" production egg layer hen was paired with a wild junglefowl collected in the Mariana and Marshall Islands that is known as the Firefox or Marquesas Island Junglefowl. It was introduced by seafarers hundreds of centuries ago, Japanese oral history has it that the founders of the Ongadori included wild roosters brought back from the Mariana Islands which are just south of Japan in the Philippine Sea.
    http://i9.photobucket.com/albums/a83/PiAmoun/Gallusinae/bekisarorange.jpg
    Mariana/Marquesas Island Junglefowl.
    http://i9.photobucket.com/albums/a83/PiAmoun/Gallusinae/720px-Philippine_Sea_location.jpg
    The f1 progeny produced from the Mariana junglecock bred to the Tosa Tomu hen were selected from, with the males with the desired traits being bred back to the mother itself or one of her full sisters. The rest of the birds were removed from the breeding program. The junglefowl sire and a few of his male progeny of the f1 were set aside. The f2 progeny produced through backcrossing with the maternal line were again selected from. The males with the most desired traits were conserved- the rest of the stock removed from breeding. This continued for eight generations. On the 9th generation, females of the f9 generation were now held back and bred back to the original Junglecock sire or on his f1 sons. This generation-is considered a new generation and is called F( capitol) a1.
    http://i9.photobucket.com/albums/a83/PiAmoun/Gallusinae/Bekisarwhite.jpg
    Generation Fa1 new sire.
    The researchers selected for white plumage as it is was very easy to distinguish at hatching. By the 18th generation, a male ( pictured below) was produced that could now be bred to an f1 hen ( pictured as well) Their offspring breed fairly true to type and extremely elongated tails and saddles are becoming increasingly common with each successful completion of an eight generation backcross.

    http://i9.photobucket.com/albums/a83/PiAmoun/Gallusinae/Totenkobackcross.jpg


    I've learned to use this backcrossing method to improve egg colour in Marandaise and Araucanian hens.

    In short straight language, the matriarch is the most important gene stock not the male. People often make the mistake of line breeding a male on to his own daughters which would work better in mammals than birds ( see founder effect and Haldane's rule). In poultry, the most parsimonious route will be to keep breeding successive generations of roosters with the most desireable aesthetic back to their mothers or the full sisters of their mothers. That first generation of females is termed the " the matriarchate". Only use a single male founder and backcross this way. If you outcross even once before three full terms- ( 8 generations X 8 generations X 8 generations of backcrossing with no new founders) you will lose your way and have to start from scratch again. New females can be brought in after the third full eight generation backcross generation ( Fc) but not before then. If any new male material is brought in you will have to start your backcrossing again.
     
  4. Sonoran Silkies

    Sonoran Silkies Flock Mistress

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    Quote:I partially disagree with this answer. Yes, there are many genes, and you must breed out all the incorrect genes, which may take a fair number of generations, but it can be done. In fact, that is the way that new colours or otjher characteristics are bred into a breed. And this is the reason that using the most similar breed possible to breed in the necessary genes is preferred over avery dissimilar breed.

    For a single gene, the first generation cross will give birds who are split for the gene: for example, if we were talking about a crest, the first generation would all be Cr/cr+. Breed those together and ~25% will be Cr/Cr, another ~25% willl be cr/cr and ~50% will be Cr/Cr. However if you breed them instead back to the crested parent, you will get ~50% Cr/Cr and ~50% Cr/cr+. Bred to the non-crested parent, they would be 50/50 cr+/cr+ and Cr/cr+.

    But getting ALL the genes to align takes multiple generations of selection for the correct set of traits.
     
  5. chicken burger

    chicken burger Chillin' With My Peeps

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    [​IMG]

    thank you all.
     
  6. karimw

    karimw Chillin' With My Peeps

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    Quote:I partially disagree with this answer. Yes, there are many genes, and you must breed out all the incorrect genes, which may take a fair number of generations, but it can be done. In fact, that is the way that new colours or otjher characteristics are bred into a breed. And this is the reason that using the most similar breed possible to breed in the necessary genes is preferred over avery dissimilar breed.

    For a single gene, the first generation cross will give birds who are split for the gene: for example, if we were talking about a crest, the first generation would all be Cr/cr+. Breed those together and ~25% will be Cr/Cr, another ~25% willl be cr/cr and ~50% will be Cr/Cr. However if you breed them instead back to the crested parent, you will get ~50% Cr/Cr and ~50% Cr/cr+. Bred to the non-crested parent, they would be 50/50 cr+/cr+ and Cr/cr+.

    But getting ALL the genes to align takes multiple generations of selection for the correct set of traits.

    Oh I agree with you. Perhaps I gave too simple an answer to a complicated question:) One parent to one daughter isn't an ideal way to start a project like that. Loss of vigor is a very real problem - take the silkied Ameraucanas for example [​IMG]
     
  7. blackdotte

    blackdotte Chillin' With My Peeps

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    If the father was white shanked (not yellow) and it produced a slate (white + black) shanked pullet it must have at least one gene for White skin, & one gene for lack of the Dermal Inhibitor.
    The Dermal Inhibitor is sex linked so a dusky shanked pullet must be at the best W/W id+/- & at the worst W/w+ id+/-.
    The white shanked father would at best be W/W Id/id+ , or W/w+ Id/id+
    So using these combinations
    Best male X best pullet = W/W Id/id+ X W/W id+/- gives 25% each white shanked males, 25% each dusky shanksed males,gives 25% each white shanked females & 25% each dusky shanked females

    David
     

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