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Friday, April 3

  1. page Dihybrid Crosses edited ... 2. Make a key using two different letters. For example, A = Brown hair, a = blonde hair, B = t…
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    2. Make a key using two different letters. For example, A = Brown hair, a = blonde hair, B = tall, b = short.
    3. Write out your choices to determine parental genotypes. Each parent genotype should have TWO of each letter (ex: AaBB, aaBb, AAbb, etc).
    {DihybridChoice.png}
    4.
    4. *NEW STEP*
    A parent that is AaBB could make an egg/sperm with an "AB" combination or an "aB" combination. A parent who is AaBb could make gametes that have an "AB" combination, an "Ab," an "aB" or an "ab." You simply need to look at all the A/B combinations possible.
    5. After determining the gametes, you can build the Punnett Square. If a parent (AaBb) has 4 possible gametes and the other parent (AaBB) has 2 possbile gametes, your Punnett Square should be a 4x2. Each set of gametes goes above by one of the boxes.
    {DiPunnett.png}
    6. Fill in the boxes and determine genotypes/phenotypes. Remember that you need to have 2 letters for the genotype and 2 descriptors for the phenotypes.
    {CompleteDi.png}
    7.
    7. Reread the
    DIHYBRID (PUNNETT SQUARE) RESOURCES
    The Biology Project- Dihybrid Problem Set
    (view changes)
    10:51 am
  2. 10:49 am

Thursday, April 2

  1. page Incomplete Dominance and Codominance edited ... INCOMPLETE AND CODOMINANCE Incomplete dominance occurs when a heterozygous genotype results i…
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    INCOMPLETE AND CODOMINANCE
    Incomplete dominance occurs when a heterozygous genotype results in a new, blended phenotype. For example, in carnations, red-flowered plants that are crossed with white-flowered plants will produce offspring with PINK flowers (a blend). There is no true dominant/recessive relationship. As a result, we do not use capital and small letters (where a small letter would show recessiveness), instead we choose two CAPITAL letters to describe the traits.
    {KeyChoiceInc.png}
    Incomplete
    Incomplete dominance also
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    incomplete dominance.
    {IncDomMerle.png}
    In humans, incomplete dominance exists as well. Sickle cell anemia occurs in people with the homozygous condition (SS), people who are normal have the other homozygous genotype (NN). The heterozygous condition results in a mild case which, it turns out, helps prevent malaria in people exposed to the parasite.
    Punnett Squares are set up the same as before, one allele by each box. Boxes are filled in and then genotypes and phenotypes of offspring can be determined.
    {IncPunnettSq.png}
    Codominance occurs when neither trait is recessive. Instead, the heterozygous individual expresses BOTH phenotypes. A common example in humans is the ABO blood group system. For blood there are THREE alleles: A, B, and O. A and B are codominant to each other. Presence of both alleles result in Type AB blood. A and B alleles are each dominant to O. An AO genotype results in Type A blood (so would AA). A BO genotype results in Type B blood (so would BB). A person with Type O blood must have an OO genotype.
    KSU incomplete dominance- practice problems
    The Biology Project-blood types tutorial
    The Biology Project- blood types problem set (I is used with A/B, i=O)

    (view changes)
    1:40 pm
  2. file IncPunnettSq.png uploaded
    1:33 pm
  3. page Incomplete Dominance and Codominance edited INCOMPLETE AND CODOMINANCE Incomplete dominance occurs when a heterozygous genotype results in …

    INCOMPLETE AND CODOMINANCE
    Incomplete dominance occurs when a heterozygous genotype results in a new, blended phenotype. For example, in carnations, red-flowered plants that are crossed with white-flowered plants will produce offspring with PINK flowers (a blend). There is no true dominant/recessive relationship. As a result, we do not use capital and small letters (where a small letter would show recessiveness), instead we choose two CAPITAL letters to describe the traits.
    {KeyChoiceInc.png}
    Incomplete dominance also occurs in animals. In dogs, a merle coloring occurs due to incomplete dominance.
    {IncDomMerle.png}
    In humans, incomplete dominance exists as well. Sickle cell anemia occurs in people with the homozygous condition (SS), people who are normal have the other homozygous genotype (NN). The heterozygous condition results in a mild case which, it turns out, helps prevent malaria in people exposed to the parasite.
    Punnett Squares are set up the same as before, one allele by each box. Boxes are filled in and then genotypes and phenotypes of offspring can be determined.

    (view changes)
    10:21 am
  4. file KeyChoiceInc.png uploaded
    10:16 am
  5. file IncKeyChoice.png uploaded
    10:11 am
  6. file IncDomMerle.png uploaded
    10:05 am
  7. page Genetics edited ... Pedigrees Dihybrid Crosses Incomplete Dominance and Codominance Karyotyping Genetic Coun…
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    Pedigrees
    Dihybrid Crosses
    Incomplete Dominance and Codominance
    Karyotyping
    Genetic Counseling
    {Picture_3.png}
    (view changes)
    9:55 am

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