1. The two plants shown below are the same species. The plant on the left shows
ID: 65630 • Letter: 1
Question
1.
The two plants shown below are the same species. The plant on the left shows the wild type height. The plant on the right has a mutation that causes a dwarf (short) phenotype.
A cross is performed between these two (parent) plants. Many F1 plants are grown and they all have wild type height. One F1 plant is self-pollinated to produce an F2 generation.
From the list below, pick all the TRUE statements.
Select one or more:
a. The dwarf parent was homozygous for the dwarf allele.
b. The wild type parent was homozygous for the WT allele.
c. The dwarf allele is dominant.
d. The dwarf allele is recessive.
e. The wild type parent could have been homozygous OR heterozygous based on the information provided.
2.
This question refers to the same plants and crosses described in the previous question.
One F1 plant is self-pollinated to produce an F2 generation. What phenotype ratio is expected in the F2 plants?
Select one or more:
a. If you plant the F2 plants you expect a 1:1 ratio of wild type to dwarf plants.
b. If you grow the F2 plants you expect 100% to show the wild type phenotype.
c. If you plant the F2 plants you expect a 3:1 ratio of wild type to dwarf plants.
3.
A small pedigree is shown below. The dark shapes represent individuals with a genetic disorder. Several possible explanations for the inheritance of this disorder are given. Is it possible to eliminate any of the explanations (i.e. the pedigree is not consistent with a particular mode of inheritance).
HINT: draw the pedigree multiple times on scratch paper and try to assign a genotype to each individual.
Could the disorder be caused by an autosomal dominant allele?
Could the disorder be caused by an autosomal recessive allele?
Could the disorder be casued by an X-lined dominant allele?
Could the disorder be casued by an X-lined recesive allele? yes or no
Could the disorder be caused by an autosomal dominant allele?
yes or noCould the disorder be caused by an autosomal recessive allele?
yes or noCould the disorder be casued by an X-lined dominant allele?
yes or noCould the disorder be casued by an X-lined recesive allele? yes or no
Explanation / Answer
Q1). TRUE statments
a. The dwarf parent was homozygous for the dwarf allele.
b. The wild type parent was homozygous for the WT allele.
d. The dwarf allele is recessive.
Q2). c. If you plant the F2 plants you expect a 3:1 ratio of wild type to dwarf plants.
Q3). The disorder was caused by an autosomal recessive allele.
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