Download Complex Genetics Problems. 1. In a trihybrid cross, a parent plant

Complex Genetics Problems.
1. In a trihybrid cross, a parent plant with alleles for flower color, seed color, and pod shape had a
genotype of PpYyIi. It was crossed with a flower of the genotype ppYyii. What fraction of offspring are
predicted to be homozygous recessive for at least two of the three characters?
2. Two parents of the same heterozygous genotype are involved in a tetrahybrid cross. Their genotypes
are FfGgHhIi. Assuming independent assortment of these four genes, what are the probabilities that F1
offspring will have the following genotypes?
a) ffgghhii
b) FfGgHhIi
c) FFGGHHII
d) FfGGhhIi
e) FfGGHHii
3. What is the probability that each of the following pairs of parents will produce the indicated offspring?
(assume independent assortment of all gene pairs.)
è
CcDdEe
b) CCDdEe
× CcDdEe è
CCddEE
c) CcDdEe
× CcDdEe è
CcDdEe
d) ccDdEE
× CCDdee è
CcDdEe
a) CCDDEE × ccddee
4. Flower position, stem length, and seed shape are three characters that Mendel studied. Each is
controlled by an independently assorting gene and has dominant and recessive expression as follows:
Character
Dominant
Recessive
Flower position
Axial (A)
Terminal (a)
Stem length
Tall (T)
Short (t)
Seed shape
Round (R)
Wrinkled (r)
If a plant that is heterozygous for all three characters is allowed to self-fertilize, what proportion of the
offspring would you expect to be as follows?
a)
b)
c)
d)
homozygous for the three dominant traits
homozygous for the three recessive traits
heterozygous for all three characters
homozygous for axial and tall, while heterozygous for seed shape
5. In a cross between AaBbCc × AaBBCC what is the probability that the offspring will be AABbCc or
AABBCC?