TRYING to LEARN some about GENETICS

Discussion in 'General breed discussions & FAQ' started by Junkmanme, Aug 5, 2009.

  1. Junkmanme

    Junkmanme Songster

    Hi Folks! [​IMG]

    Knowing that there are a goodly number of folks on THIS Forum who have considerable understanding of chicken genetics and also have years of practical experience, I have a question about breeding:

    I have a Rooster that I believe is some sort of Red Sex-Link (picture follows).

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    I also have a Black Roundhead Game Hen that is in her 3rd week of setting 8-10 eggs. Should get a hatch any day now, if fertile. (picture follows)

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    THE QUESTION:

    In an attempt to use the "Chicken Calculator" to perceive just WHAT the chicks might grow to look like, the "Punnett Square" showed 4 possibilities:

    1.) Half of the Roosters will be ALL BLACK.
    2.) Half of the Roosters will be ALL WHITE.
    3.) Half of the Hens will be ALL BLACK
    4.) Half of the Hens will be ALL WHITE.

    This result seems "unlikely" to me. I would expect much more of a variety in the mixture.....perhaps even a "Partridge" coloring.

    What does your education, experience, and "gut-feeling" tell you about the offspring of this mating?

    Note #1: The picture of the Rooster IS the actual Rooster.

    Note #2: The picture of the Hen IS NOT the actual hen, but VERY REPRESENTATIVE except MY HEN does not have the barring of the hen in the picture. Also, In the ancestry of MY HEN, there is SOME "Asil" (Aseel). My hen is SOLID BLACK.



    What is your opinion of the "likely" results of this mating?

    THANKS for ANY opinions !!!
    -Junkmanme- [​IMG]
    [​IMG] [​IMG] ????? [​IMG]
     
    Last edited: Aug 5, 2009
  2. Sonoran Silkies

    Sonoran Silkies Flock Mistress

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    One thing you need ot realize is that there is more than one way to make a number of varieties. To a large extent, the calculator makes some assumptions that may or may not hold true for an individual bird. Depending on the assumptions, the outcome can vary dramatically.

    The cock looks to be het for dominant white. I think the calculator would assume E/E, but that is not necessarily the case, and could alter the outcome, with solid black hiding patterns.
     
  3. Junkmanme

    Junkmanme Songster

    THANK YOU, Sonoran Silkies, for YOUR response !

    I think I understand your comment to mean that the "Chicken Calculator" will give results based on the probabilities of the inputs (which MAY or MAY NOT be correct INPUTS of the Genetics of any particular bird.)

    In order to get "accurate" results in the "Punnett Square", one must be sufficiently "conversant" in the genetics of the particular fowls involved AND the terminology used.

    THIS is the PRIMARY reason I have posted this thread. I can and DO read the info available to me re: Genetics...but, I MUST ADMIT that much of the time, while reading this stuff, I get LOST in the terminology and the seemingly "obvious" conclusions which I have difficulty following....

    By-the-way.WHAT does het mean? My guess is that it means something like "hereditarily E+ dominant Trait. (I'm quite SURE that my guess is WRONG.)


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    [​IMG]-Junkmanme- [​IMG] [​IMG]
     
    Last edited: Aug 5, 2009
  4. Sonoran Silkies

    Sonoran Silkies Flock Mistress

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    Quote:Het is short for heterozygous, meaning that the two copies of a gene are not the same allele. The opposite is hom, or homozygous, where the alleles are the same.

    Except for the sexlinked genes, all birds have two copies of every gene. Each gene has two or more alleles, or variations. For example, the blue gene alleles are Bl (blue) and bl+ (not-blue), the barring gene alleles are B (barred) and b+ (not-barred), the pattern gene alleles are Pg (patterned) and pg+ (not-patterned). The + symbol refers to wild-type, the allele carried by the red jungle fowl, essentially the default allele.

    A few genes have multiple alleles; black and dominant white are among these. For black the alleles are E, E^R, E^Wh, e+ and e^b; for white the alleles are I, I^s, I^d & i+.

    So, when I said het for dominant white I mean that the bird likely has one copy of I and the 2nd copy is one of the other alleles, likely i+, but it could be one I^s (unlikely, as the allele is quite rare) or I^d. A bird who is hom for dominant white would be I/I, and solid white, although small amounts of colour might leak through, but not large amounts as on your cock's wing bars.
     
  5. Junkmanme

    Junkmanme Songster

    THANK YOU again, Sonoran Silkies!!!

    IF I understand this "allele" thing correctly, an "allele" is a "set" of potential differences in a gene at a particular point on a chromosome or on the DNA spiral.

    So, at each point on this "spiral", there are various genes which can attach at this point, generally preclude the attachment of other genes at the same point. AND, this CAN be accomplished in a sometimes "random" fashion. (Which of the "alleles" GETS there "firstest with the mostest"...???)

    Also, IF I understand this somewhat, a gene at one particular "allele" can be blocked-out or Overcome by a particularly STRONG GENE at another allele?

    Could we refer to an "allele" as a "parking-spot" that several different cars (genes) are trying to get to first? BUT, only certain size cars can get into that parking spot? (NO Cadillacs in a small spot layed out for Hondas?)......or am I totally missing the point here?

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    THANKS for trying to HELP ME to understand!!!

    [​IMG] -Junkmanme- [​IMG] [​IMG]
     
    Last edited: Aug 5, 2009
  6. Sonoran Silkies

    Sonoran Silkies Flock Mistress

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    I'm late leaving for physical therapy (hurt my back coop building [​IMG] ), so I'll give a very short answer now and more later.

    Could we refer to an "allele" as a "parking-spot" that several different cars (genes) are trying to get to first? BUT, only certain size cars can get into that parking spot? (NO Cadillacs in a small spot layed out for Hondas?)......or am I totally missing the point here?

    The parking spot is the gene; there is assigned parking. Several cars (the alleles) can fit ONLY into that space; they cannot park elsewhere, and no other cars can park there.

    Go look at the chicken calculator--many of the genes are listed, along with the allele combinations available. That will show you a graphic representation.​
     
  7. Junkmanme

    Junkmanme Songster

    THANKS AGAIN!

    I hope they let you sit in a NICE "hot-Tub" for the Physical Therapy! (It always does my back so much GOOD that I feel 40 years younger for a little while!) [​IMG]

    I'll THINK on what you have GIVEN me to try to understand!

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    -[​IMG]-Junkmanme- [​IMG]
     
  8. Junkmanme

    Junkmanme Songster

    Ah So......"Sonoran Silkies"..........

    So, I DID NOT understand.

    BUT, the "Analogy" is useful. My mistake was confusing the "Gene Location" (parking spot) with the "allele" (car authorized to park there). Hmmm --- MAYBE this is starting to fit together in my perception of the mechanisms of Genetic Expression!!!

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    YOU truly do have a "TALENT" for TEACHING !!!!

    Perhaps Tim Adkerson will "stumble upon" this thread and add HIS knowledge to this thread. I have noticed some of his comments and have felt that they were very educational and well-educated also.

    SOMETIMES the "simplest things" prevent the brain from absorbing the information! When I was a High School Student in an "Advanced Math Select Group", I did 2 years of Algebra and didn't understand a darn thing! When I studied Trigonometry. ALL OF a SUDDEN. Algebra FINALLY made sense to me! Geometry seemed almost "natural....but the "formulas of algebra had seemed like "chicken scratching"....(EMPTY FORAGING!)

    It's not obvious just WHERE the "BLOCK" to Understanding MIGHT
    BE LOCATED, but "analogies" (written picture-images) can HELP route the information around the conceptual "Blockage".

    THANK YOU..I believe that I am beginning to understand!

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    [​IMG]-Junkmanme- [​IMG]
     
  9. Sonoran Silkies

    Sonoran Silkies Flock Mistress

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    I generally use analogies to explain--it seems to make less familiar ideas easier to grasp. I too found geometry & trig far more understandable than algebra, but that is directly opposite of the rest of my family.

    First, some terminology:

    Gene--A piece of DNA located at a specific locus on the chromosome.

    Allele--alternative genetic expression for a specific gene. The alleles for andalusian blue are Bl & bl; the alleles for columbian are Co & co; the alleles for black are E, E^R, E^Wh, e+ & e^b; the alleles for recessive white are C, c, c^re, c^a; etc.

    Dominant--A single copy of the allele will cause the trait to express, regardless of another allele's presence in the organism. There is no obvious difference between a heterozygote and a homozygote. Examples would be Co, Fm, Mh, O, R.

    Incompletely Dominant--A double copy of the allele results in complete expression of the trait, whereas a single copy of the allele results in an intermediate expression of the trait. Examples would be Bl, Di, F, I, Ml, S.

    Recessive--The trait is expressed only when no other allele is present in the organism. Examples would be lav, choc, c, h, ig, lav, mo, w.



    The analogy on explaining genes versus alleles that I usually use is a shape sorter box (child's toy). Think of the gene and its location as being the same thing, just different terms. Think of each gene as a different shaped hole--only blocks that fit that hole go there. So the circle-shaped hole has circular blocks, the triangle-shaped hole has triangular blocks, the star-shaped hole has star-shaped blocks. All the circular blocks are alleles to the circular hole, regardless of whether they are red or green or purple. Likewise, all the star-shaped blocks are alleles of the star-shaped hole, regardless of colour.
     
  10. blackdotte

    blackdotte Songster

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    The typical Sex linked male is a Dominant White Wheaten based bird, if the hen is Black my best guess it that you will get predominantly white chicks, that may or may not show a little colour.
    David
     

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