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Homework Help: Hello everyone,i'm havin trouble with this genetics problem.any ideas?

  1. Oct 13, 2007 #1
    1. The problem statement, all variables and given/known data

    You know grey paws(GG or Gg) is dominant to pink paws(gg).You also know that brown eyes(an x linked trait:BB,Bb, BY) is dominant to green eyes (bb or bY). You have a male dog with grey paws and brown eyes and a female dog with pink paws and brown eyes.They mate and have 8 puppies:

    2 females with grey paws and brown eyes 2 females with pink paws and brown eyes

    1 male with grey paws and brown eyes 1 male with pink paws and brown eyes

    1 male with grey paws and green eyes 1 male with pink paws and green eyes

    what are the parents genotypes?

    3. The attempt at a solution

    just want a head start on how to solve this problem.
  2. jcsd
  3. Oct 14, 2007 #2


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    Science Advisor
    Homework Helper

    First it is two question so treat each one independently.
    Making a matrix of possible combinations comes to mind.

    What can you say about an x linked trait?
    Where does a male puppy get its x contribution from?
  4. Oct 14, 2007 #3
    so i have to find the genotype of first the mother and secondly the father.for the mother, i made a matrix of
    also i know that x linked traits are maternally inherited.thus the male puppy will get it from its mother.
    these are the matrixes i came up with so far

    BB crossing gg, Bb with gg, BY with gg

    BB with GG, Bb with GG, BY with GG,BB with Gg, Bb with Gg, and BY with Gg.
    so how do i determine the genotypes now?
  5. Oct 14, 2007 #4


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    Science Advisor
    Homework Helper

    You want two matrices. One for the eyes one for the paws. You can put them together later.

    Since you need to eliminate one what can you say about the alleles B, b and Y?
  6. Oct 15, 2007 #5
    Genetic Problem

    The alleles B,b and Y are dominant to green eyes.so do i eliminate eliminate Bb and BY?So the cross for the mum will be BB and gg?
  7. Oct 15, 2007 #6


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    Staff Emeritus
    Science Advisor

    As NoTime mentioned, treat paws and eyes independently.

    Write the phenotypes for female brown and green eyes, and male brown and green eyes.

    Who has BY and who has bY? What is the sex of Bb?
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