BIOLOGY 1406 ASSIGNMENT: Genetics Lab
Dr. Solti 2014
Name: _______________________________
Monohybrid Crosses:
1. An albino woman marries a normally pigmented man and they have 13 children. Seven
children are normally pigmented and six are albino. What are the genotypes of the parents and
children?
2. In peas, tall plants are dominant to short plants. State the genotypes and phenotypes of the
following crosses:
a.) heterozygous X heterozygous
b.) heterozygous X short
c.) homozygous tall X short
d.) heterozygous X homozygous tall
3. A blue-eyed woman, both of whose parents were brown-eyed, married a brown eyed man,
whose mother was blue-eyed and whose father was brown-eyed. Assuming brown is dominant
to blue, what are the possible genotypes of the woman, man, their parents, and their children?
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BIOLOGY 1406 ASSIGNMENT: Genetics Lab
Dr. Solti 2014
4. A couple who are both carriers for the cystic fibrosis gene have three children with cystic
fibrosis. What is the probability that their next child will have cystic fibrosis?
Incomplete Dominance:
5. In snapdragons, heterozygotes have pink flowers and the homozygotes have either red or
white flowers. When plants bred for red flowers are crossed with plants pure bred for white
flowers, what percentage of the offspring will have pink flowers?
Dihybrid Crosses:
6. One gene has alleles R and r. A second gene has alleles M and m. For the following
genotypes, what kinds of gametes may be formed? (Hint: use FOIL)
a.) RrMm
b.) RRmm
c.) rrMm
d.) Rrmm
7. What are the genotypic ratios of the offspring from the following crosses: (Hint: use FOIL to
get gametes, and then use Punnett Square to do crosses)
a.) RrMm X RRMM
b.) RRmm X RrMm
c.) rrMm X rrMm
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BIOLOGY 1406 ASSIGNMENT: Genetics Lab
Dr. Solti 2014
8. The ability to roll the tongue and have a widows peak are dominant traits. A woman
heterozygous for rolling the tongue and widows peak marries a man who is homozygous
recessive for both traits. What genotypes might their children have?
9. A couple has two children, each having brown eyes and blond hair. Both parents are
homozygous for brown eyes (BB), but one is a redhead (Rr) and one is a blond (rr). What are the
possible genotypes of the children?
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BIOLOGY 1406 ASSIGNMENT: Genetics Lab
Dr. Solti 2014
Pedigree:
10. Assign correct genotypes to the squares and circles of the following pedigree: where A =
normal foot arches and a = flat feet. (Hint: Squares are male and circles are female...but sex
doesn't matter)
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BIOLOGY 1406 ASSIGNMENT: Genetics Lab
Dr. Solti 2014
Sex-Linked Pedigree:
11. Color blindness is sex linked. Assign the correct genotypes to the squares and circles of the
following pedigree, where B = normal vision and b = colorblind. Hint: Open square = normal
vision male, colored square = colorblind male; open circle = normal vision female; colored
circle = colorblind female
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