1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Incomplete Dominance Question Grade 11 Need an biology expert

  1. Mar 16, 2012 #1
    1. The problem statement, all variables and given/known data

    Hey guys...

    The palomino horse results from the combination of two incompletely dominant genes, one codes for the colour chestnut and the other for cream. Determine the expected genotypic and phenotypic ratios for the following crosses:

    a.)chestnut and cream
    b.)palomino and cream
    c.) palomino and palomino


    Please this is the only question I didn't understand for my homework.. However I got 100% for phenotype for all options... Please correct me if I'm wrong and tell me what I'm doing right and wrong but mostly wrong :)

    2. Relevant equations

    What :S :?

    3. The attempt at a solution


    Let PP represent the allele for palomino.
    Let PC1 represent the allele for cream.
    Let PC2 represent the allele for chestnut.


    a.)

    _____PC1______PC1
    PC2__PC1PC2___PC1PC2
    PC2__PC1PC2___PC1PC2


    Genotype: 50% Cream; 50% Chestnut
    Phenotype: 100% PC1PC2


    b.)


    ____PC1____PC1
    PP__PPPC1__PPPC1
    PP__PPPC1__PPPC1


    Genotype: 50% Cream; Palomino 50%
    Phenotype: 100% PPPC1

    c.)


    ____PP____PP
    PP__PPPP__PPPP
    PP__PPPP__PPPP


    Genotype: 100% Palomino
    Phenotype: 100% PPPP
     
  2. jcsd
  3. Mar 17, 2012 #2

    Ygggdrasil

    User Avatar
    Science Advisor

    A few points:

    1) When the question asks about about genotype ratios, it's talking about the different combinations of alleles. For example, 50% PC1PC2, 50% PC1PC1 is a genotype ratio. A phenotype ratio would describe the numbers of horses of each color, for example, 50% palomino, 50% cream.

    2) Pp is not the allele for palomino. In fact, phenotypes are not represented by a single allele. Rather, phenotypes are associated with pairs of alleles (e.g. PC1PC1 gives the cream phenotype, whereas Pc2Pc2 gives the chesnut phenotype). Read the question again, focusing on the first two sentences. What is the genotype associated with the palomino phenotype? If you still don't understand, you may need to re-read the section in your textbook on incomplete dominance.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Incomplete Dominance Question Grade 11 Need an biology expert
Loading...