Explore BrainMass
Share

Explore BrainMass

    Genotypes & Punnett Squares

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    In fruit flies, the phenotype for eye color is determined by a certain locus. E indicates the dominant allele and e indicates the recessive allele. The cross between a male wild type fruit fly and a female white-eyed fruit fly produced the following offspring.

    Wild-type Wild-type White-eyed White-eyed Brown-eyed
    male female male female female
    F1 0 45 55 0 1

    The wild-type and white-eyed individuals from the F1 generation were then crossed to produce the following offspring.

    F2 23 31 22 24 0

    (a) Determine the genotypes of the original parents (P generation) and explain your reasoning. You may use Punnett squares to enhance your description, but the results from the Punnett squares must be discussed in your answer.
    (b) Use a Chi-squared test on the F2 generation data to analyze your prediction of the parental genotypes. Show all your work and explain the importance of your final answer.
    (c) The brown-eyed female in the F1 generation resulted from a mutational change. Explain what a mutation is, and discuss two types of mutations that might have produced the brown-eyed female in the F1 generation.

    © BrainMass Inc. brainmass.com October 9, 2019, 7:49 pm ad1c9bdddf
    https://brainmass.com/biology/genetics/genotypes-punnett-squares-130311

    Attachments

    Solution Preview

    In fruit flies, the phenotype for eye color is determined by a certain locus. E indicates the dominant allele and e indicates the recessive allele. The cross between a male wild type fruit fly and a female white-eyed fruit fly produced the following offspring.

    Wild-type Wild-type White-eyed White-eyed Brown-eyed
    male female male female female
    F1 0 45 55 0 1

    The wild-type and white-eyed individuals from the F1 generation were then crossed to produce the following offspring.

    F2 23 31 22 24 0

    (a) Determine the genotypes of the original parents (P generation) and explain your reasoning. You may use Punnett squares to enhance your description, but the results from the Punnett squares must be discussed in your answer.

    The original parents were wild-type males and white-eyed females. If the males had the Ee genotype and the females had the ee genotype, then half of the offspring should be wild-type (Ee) and half of the offspring should be white-eyed (ee):

    E e F1: 50% Ee, 50% ee
    e Ee ee
    e Ee ee

    If ...

    $2.19