Basic Genitics

Discussion in 'Peafowl' started by KsKingBee, Oct 24, 2014.

  1. KsKingBee

    KsKingBee Overrun With Chickens

    I have really been enjoying reading the Genetic thread but it is quite a bit over my head in some places. Can we have a place to ask just the basics for us new peabrains?

    I am trying to get my brain around a couple of the basics and think I understand but would like a little confirmation. Last breeding season I had three breeding pens;

    A pen with IB x IB, no questions there except for some color variances which I may ask about later.

    A pen with IB Pied WE cock (I suspect split Cameo), and IB, IB Pied, and Cameo hens.

    And a pen with a IBBS cock (I suspect carry Cameo split), with IB, and Cameo hens.

    Do I understand right that a Cameo hen will not produce Cameo chicks unless the cock is also carrying the Cameo also? If not then my cocks are carrying Cameo. If they can then my assumption is wrong and the cocks do not really carry Cameo.

    Does BS work the same way? I produced some BS chicks but I do not have any BS hens. Do my Cameo hens hide BS in them to produce BS chicks?

    Another basic question, sorry if it is too much in one post, but if you cross two single factor WE birds will that produce double factor chicks?
     
  2. Arbor

    Arbor Chillin' With My Peeps

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    Hopefully this helps, and is not confusing :rolleyes:
     
    Last edited: Oct 24, 2014
  3. KsKingBee

    KsKingBee Overrun With Chickens

    WOW! And Thank You! [​IMG] I have had some good instructors trying to teach me but I got confused and you really cleared it up for me. I guess I have some really mixed up birds but that gives me a lot to work with. My main two breeding cocks last year are
    IBBS split Cameo - does not show any Cameo but some of the IB chicks he threw do have a little light tan color in between the brown and the cream on the chest. I don't know what to make of that.
    Now it is confirmed that at least one of the Cameo hens is split BS as I raised both BS and Cameo BS (Oaten), chicks from him.

    The other Cock is IB Pied WE split Cameo, he also does not show any Cameo and is a single factor WE as only about a third of his eyes are white.
    At least one of the Cameo hens is split white or Pied as I got two Cameo Pied chicks from that pen.

    OK, may I ask another basic question?

    Do Cameo hens normally have a dappling of white tipped feathers on her back or is this a sign of some kind of mix? My WE hens have a few white tipped feathers on their backs so I am wondering if this is a sign of WE or BS in the Cameo hens.
     
  4. Arbor

    Arbor Chillin' With My Peeps

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    It can mean the presence of w/e. However, cameo is a colour that can fade a lot, is the white seen all year long? One way to find out is to do test breedings with a male that is known NOT to carry w/e. If you hatch a few males that grow out to have it, then you know for sure. The IB chicks that show some tan colour is just a sign of good variation among IB. With the breeding I've done, there have been no signs of any differences between males that are split to sex-linked colours and those that are just IB.
     
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  5. Rosa moschata

    Rosa moschata Chillin' With My Peeps

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    Punnett Squares are often used to predict offspring when one knows the genotypes of the parents. However, if you DON'T know for sure if your parent birds are split to things, you can certainly use the Punnett Square -- in reverse. You set it up with as much information as you know about the parents and their offspring. If you get "surprises" in the offspring that don't seem possible based on what you "see" in the parents, then you know the parents are splits.

    For the sex-linked mutations, female offspring get their Z chromosome only from dad (since mom gives the W chromosome, which makes them daughters instead of sons). So if you get Cameo daughters, then Dad must be either Cameo or split to Cameo. Sons, on the other hand, have two Z chromosomes -- one from each parent. So if you get Cameo sons, then the gene must come from BOTH parents -- which means mom MUST be Cameo (females can't be split to sex-linked mutations, since they have only one Z chromosome), and Dad MUST be Cameo or split to Cameo.

    For the other mutations (not sex-linked), to get two copies in the offspring, again you must have each parent having at least one copy to pass on. So you got "surprise" Blackshoulder offspring from parents which weren't visual for Blackshoulder. Well, that means BOTH parents must be AT LEAST split to Blackshoulder. Or one could be visual and the other split. Or both could be visual. But either way, Blackshoulder has to come from both parents (visual or split) for it to be visual in the offspring.

    It becomes easy -- if you get a "surprise" offspring, figure out what it needed to look like that (i.e. two copies of Blackshoulder). Then look at the parents. OK, mom was Blackshoulder. Dad doesn't look Blackshoulder, but for this offspring to happen, he MUST therefore be split to Blackshoulder. This is how test-breeding will tell you what your parent birds have but don't show (i.e. what they're split to).

    White-Eyed is similar -- except that it is "somewhat visual" in birds which are split to White-Eyed. I say "somewhat" because these birds have fewer white ocelli than do birds with two copies of White-Eyed. This is what's called "incompletely dominant", and you'll often hear these types of mutations being referred to as "Single Factor" and "Double Factor." In terms of how they are inherited, think of "Double Factor" as working the same as being visual for Blackshoulder -- in both cases, the birds have two copies. But what makes White-Eyed easier is that you can easily tell the splits (i.e. Single Factor White-Eyed) from those who don't have the mutation (i.e. anything NOT White-Eyed). So, just as in Blackshoulder, to get offspring which are Double Factor White-Eyed, you'll need BOTH parents to have the mutation. This could mean Single Factor X Single Factor (gives 25% Double Factor offspring), or Single Factor X Double Factor (gives 50% Double Factor offspring), or Double Factor X Double Factor (gives 100% Double Factor offspring).

    Remember in the other thread when I mentioned "probability math" for determining percentages? One thing I forgot to mention is that the 50% thing refers ONLY to splits. If a bird has two copies of a mutation, then 100% of its offspring will inherit one copy from that parent. Similarly, if a bird does NOT carry or show a mutation, then 100% of its offspring will NOT inherit one copy from that parent. So here's an example:

    Blackshoulder X split to Blackshoulder

    The Blackshoulder parent has two copies of the mutation -- therefore it will pass one copy of the mutation to 100% of its offspring.

    The other parent has only one copy of the mutation -- therefore it will pass one copy of the mutation to 50% of its offspring.

    This becomes more important when you're dealing with multiple mutations.

    Opal Single Factor White-Eyed split to Blackshoulder X IB Blackshoulder Double Factor White-Eyed split to Opal

    So what are the odds of getting an Opal Blackshoulder Double Factor White-Eyed? See if you can figure it out, KsKingBee!

    :)
     
    Last edited: Oct 24, 2014
  6. KsKingBee

    KsKingBee Overrun With Chickens

    WE bought at auction from a breeder that was selling off all his stock last March and most of the birds were roughed up from lack of care or from being caged for the auction. They all look much much better now that they have molted the colors are brighter than they were last summer. I think that might make the white more noticeable.

    Test breeding? that is why I am trying to figure out what I have so I can be more selective in my parings, being over 60 I might want to think about long term commitments. [​IMG] That is why I am asking about these noticeable differences and looking for clues about what TO look for.

    Thanks for your input!
     
  7. KsKingBee

    KsKingBee Overrun With Chickens

    Thank you Rosa! And thanks for the answer, 50%. That is what I would expect from pairing my IB pied single factor WE cock to my IB (supposed) double factor WE hens, 50% double factor chicks. I suppose that 25% would be Pied and another 25% IB?
     

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