Playing with Punnett Squares and Genetics

Discussion in 'General breed discussions & FAQ' started by perryalana21404, Dec 12, 2012.

  1. perryalana21404

    perryalana21404 Out Of The Brooder

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    Oct 16, 2012
    Hello all!

    Could use a little assistance with gene sets and how they interact with each other please.

    Background: Was looking at my flock of various breeds and was daydreaming about controlled breeding, and who would go with who. A Meyers Hatchery rooster crossed my path in pursuit of a hatchery grade RIR hen. (Don't know her origins, but doesn't look much like the exhibition reds I've seen.)

    So, end result, a Red Barred Rhode Island Rock! That could be a pretty cool bird.

    Next step, finding gene sets and plugging them into Punnett squares. Not so easy. Turns out there are several different opinions and/or strains with different gene sets between strains, especially with exhibition vs hatchery birds. Oh great!

    First question: What gene sets should I use for each bird?
    Rooster = Meyer stock Barred Rock
    Hen = hatchery grade RIR

    In my speculation I came up with a grossly over-simplified (and perhaps completely faulty) gene set to play with.

    I called the black in the barred rock 'E' and in the RIR called it 'e'.
    The barring I called 'B' and solid for the RIR 'b'.
    Therefore:
    Barred Rock Rooster = E/E B/B
    RIR Hen = e/e b/-
    (somewhere I thought I read, and seem to witness in my flock, that black and barring are both dominant, so I'm going with that!)

    Here is what happens:

    -F1 are going to be all barred and the males will be all hetero.
    -Breed F1 rooster over a RIR hen (using my imaginary gene set) and I get an equally distributed mix, male and female of both solid and barred and both red and black colored birds. (Naming these F2.)
    -Take F2 Red Barred Rooster with F2 Red Barred Hen and the results are mostly Red Barred birds, but the males are 50% hetero and 50% homo for red barring while the hens are 50% solid red or barred red. Calling these F3
    -Breed a F3 test Red Barred Rooster back to a F2 or F3 control Red Barred Hen (control because of the sex link lack of hidden recessives.) If the mating throws a small percentage of solid red females then he is hetero and needs to be culled. If they throw only red barred males and females then he is a double-dose e/e B/B and will breed pure in successive generations for red barring.


    OKAY, time to leave fantasy land. I KNOW that it isn't as simple as that. I've read things like mahogany and wheaten genes in RIR, and there are various forms of 'e' that only seem to confuse me, like maybe the barring is modifier of the black and not a gene on a different allele (which is what I think I did, made 'B' on a different allele, right?)

    Is anybody out there willing to 'take me under their wing', so to speak, and help me understand what is really going to happen? Anybody with the patience to walk me through the subtle and not-so-subtle differences in genes/modifiers and there effects on the phenotypes that I see walking around my yard? I have a basic high school understanding of genetics, and every time I start looking at the chicken gene sets I find myself overwhelmed and confused by the interplay of so many genes/modifiers. Eager student/apprentice wondering where to start. Created the above cross to whet my mind and to illustrate what I do and do not understand yet.

    Anybody got input?
    Thanks
    Perry
     
    Last edited: Dec 12, 2012
  2. tadkerson

    tadkerson Chillin' With My Peeps

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    With what you are doing is simple. You do not need to know any more about genetics than what you have posted. If you back cross a male (F1, BC1 etc. ) to the rhode island red females make sure the male is barred. Each time select a male that has the darkest red color. You should get some good looking birds from the BC2. Then stop back crossing and cross an BC2 barred male with an BC2 barred female. The light colored BC2F1 males carry two barring genes the darker BC2F1 males carry one barring gene. Only use the lighter colored males as breeders.

    Something you left out is that the birds can be silver or gold.

    You have to select for a red and barred male in the BC1. The BC1 chicks with white down can be silver or red you will not know until they get older.



    Barred male X RIR =F1 (all black and barred chicks) Hatch 10 chicks.

    F1 male X RIR=BC1 ( use BC1 chicks for breeding that have a white down or white down with dark markings, do not use black chicks for breeding) Select a red barred male. Hatch chicks until you get a red barred male.

    BC1 red barred male x RIR=BC2 (good looking birds all chicks should have white down and be red as adults)

    BC2 x BC2= BC2F1 select for light colored males




    Tim
     
    Last edited: Dec 13, 2012
  3. perryalana21404

    perryalana21404 Out Of The Brooder

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    Thank you VERY much. Your reply is EXTREMELY helpful. The silver and gold part is a bit confusing, but it puts us on the right path for further research.

    I think what I am reading is that the silver and gold colors will show up as solid colored non barred birds. Correct? Silver looks light there for barring will not show? Does the gold represents the red that we will see in both solid and barred birds? Or are the silver and gold colors in addition to the red color?

    Thank you for reminding us about the barring gene enhancing its self in homozygous birds. That will make culling hetero birds that much easier.

    We are very curious about the genetics involved and love working Punnett squares. If you know the gene sets we would love to know more about them.

    Thank you again. This is very exciting!!!!

    Perry
     
  4. tadkerson

    tadkerson Chillin' With My Peeps

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  5. Henk69

    Henk69 Chillin' With My Peeps

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    If you truely like playing with punnett squares go to http://kippenjungle.nl/kruisMatrix.html

    For BC1 enter in male field: E/E^Wh,B/b+,Mh/mh+,S/s+,Co/co+
    female (RIR parent): E^Wh/E^Wh,b+/-,Mh/Mh,s+/-,Co/Co

    Click "Punnett square" to generate the punnett square
     
    Last edited: Dec 14, 2012
  6. perryalana21404

    perryalana21404 Out Of The Brooder

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    Wow!
    Thank you too Henk69.

    You gave me:
    "For BC1 enter in male field: E/E^Wh,B/b+,Mh/mh+,S/s+,Co/co+
    female (RIR parent): E^Wh/E^Wh,b+/-,Mh/Mh,s+/-,Co/Co"

    Were can I find these gamete formulas?? I'm going crazy trying to find any kind of reference site that lists the gene combinations for different breeds. Is there such a thing? The Punnett Square Generator is incredible, but I am limited in not knowing any gene sets. I thought I might be able to deduce some from the generator but it uses phenotype descriptors instead of breed names. I had no idea that a RIR was more accurately a 'black patterned red columbian'!

    Ok, looking at your RIR gene set compared to the BC1 you provided, I might be able to reverse engineer the Barred Rock father to be:

    E/E,B/B,mh+/mh+,S/S,co+/co+
    (or any combination of hetero B and S)
    Correct?

    Tim's suggestion to breed BC1 back to RIR (and you reinforcing it) made it evidently clear that I was missing some key information in my first E/E,B/B calculations because doing the BC1 x RIR yields exactly the same results as BC1. Gonna be fun seeing pictures of the crosses too!

    Thank you sincerely. I'm climbing the learning curve. Keep it coming!
    Perry
     
  7. Henk69

    Henk69 Chillin' With My Peeps

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  8. tadkerson

    tadkerson Chillin' With My Peeps

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    Doing a BC1 x RIR cross will improve the looks of the barred birds. Clears up the black smut and really bad barring.Trust me I have done the crosses.


    [​IMG]


    By back crossing you are working toward a homozygous bird like the rhode island and getting away from the black barred bird. The only trait you want to keep introducing from the barred rock in the offspring is the barring.

    The barred rock is silver and if he is the father every bird will be silver. F1 males will carry a silver and a gold allele. By back crossing with a gold (RIR) hen you are insuring that some of the male offspring will be homozygous for gold and some of the females will be gold also. This eliminates the silver allele in the next generation.


    You are ok on the rock father.



    wheaten ey/ey or ewh/ewh,

    columbian Co/Co or a columbian like restrictor


    mahogany Mh/Mh,
    gold s+/s+ or s+/_w ,
    single comb p+/p+ r+/r+,
    autosomal red ( I know they have autosomal red it segregated during my breeding experiments) Most likely more than one gene involved dominant and recessive- just my thoughts)
    under color red due to wheaten and Mh



    Tim
     
    Last edited: Dec 16, 2012
  9. perryalana21404

    perryalana21404 Out Of The Brooder

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    Ok, thanks Tim. I suspected something along those lines of strengthening the red barring, just couldn't see it in my oversimplified Punnett gene set. Using the calculator I was able to understand what you were saying more clearly. The pic really helps too! Cool looking bird.

    Henk69, that calculator is incredible. Simply amazing. I've spent much time there already and can see hours of experimenting and researching on that site in my near future. Once I get my head around the Barred Rock x RIR crossing possibilities (like other possible color/pattern strains that could be isolated) I will probably use the calculator to backtrack on some White Silkie x Tan Frizzle Chochin crosses we have running around the farm.

    We have 5 birds from that hatch that are across the spectrum in appearances. They all have feather feet and extra toes like the silkie, as well as the silkie type comb, and all seem to have an intermediate form of silkiness that displays normal type feathers but are noticeably silkier for a lack of any better way to describe it.
    2 roosters are white feathered pink skins.
    1 hen is white feathered black skinned (the white has a very faint, almost dirty looking red showing through,)
    1 hen is a black and tan patterned black skin,
    1 hen is a tan patterned frizzle black skin.

    Should be fun to explore what happened with them genetically. Also they have started mating into the General Population flock so things are going to start getting crazy! We are already starting to see what *might be a partial frizzle feather on a chick with white tipped black feathers, plus 2 other younger chicks are starting to show the same feathers standing outward as the older chick above. They are not 'curled' feathers yet, but just appear to be standing slightly perpendicular to the skin. These chicks were from large brown eggs so it would appear that our sizzle cross roosters have been active. We don't have any other frizzles in the flock. Have plans to segregate these 5 into their own breeding flock to see what combinations are thrown in their F2, purely out of curiosity. Having the Henk69 calculator at my disposal I should be able to narrow down what the possible F2 birds will look like before hatching them. EXCITING!!

    Thank you both for your wonderful input. You have both helped me break through the barrier of basic confusion.
     
  10. perryalana21404

    perryalana21404 Out Of The Brooder

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    Oct 16, 2012
    Tim,
    not quite sure what to make of the autosomal red, it is a bit beyond my comprehension right now. How is this different from the gold/mahogany/wheaten red?
     

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