Download Beyond Complete Dominance Worksheet

Beyond Complete Dominance Worksheet 1 Beyond Complete Dominance Worksheet
Name ______________________________
1. For the peas Gregor Mendel worked with, purple flower color (P) is dominant
over white flower color (p). If a homozygous purple-flowered plant is crossed
with a white-flowered plant, list the possible phenotypes and genotypes, and
include the ratios of each. Show the Punnett square you used to answer the
question.
2. In cows, the allele for red hair (HR) and the allele for white hair (HW) are
codominant. The heterozygous condition results in a mixture of red and white
hairs and the cows are called roan. What would occur if a red cow was crossed
with a roan cow? Show the Punnett square as both the genotypic and
phenotypic ratios.
3. Sickle cell anemia is a trait that exhibits incomplete dominance. A person with
an AA genotype does not have sickle cell anemia, and a person with an SS
genotype has full sickle cell anemia. A person with an AS genotype will have
some sickle-cells, though s/he might show minimal or no symptoms (a
“carrier”).
Englebert is a carrier for sickle-cell anemia (shows some symptoms), and his
wife, Gwendoline, does not. What are the chances that Engelbert and
Gwendoline will have a child with ANY sickle-shaped blood cells? Show your
work!
4. Draw a Punnett square showing all the possible blood types for the offspring
produced by a type “O” mother and an a Type “AB” father
5. Mrs. Clink is type “A” and Mr. Clink is type “O.” They have three children
named Matthew, Mark, and Luke. Mark is type “O,” Matthew is type “A,” and
Luke is type “AB.” Based on this information:
a. Mr. Clink must have the genotype ______
b. Mrs. Clink must have the genotype ______ because ___________
has blood type ______
c. Which child can NOT be the offspring of these parents?
Beyond Complete Dominance Worksheet 2 6. In a species of Birds, incomplete dominance between alleles for black (B) and
white(w) feathers is observed. Heterozygotes are blue. If two blue birds are
crossed, what will be the possible genotypes and phenotypes of the offspring?
7. A tall, yellow-seeded pea plant heterozygous for height and seed color (TtYy) is
crossed with a tall, green-seeded pea plant that is heterozygous for height but
homozygous recessive for seed color (Ttyy). If 80 offspring are produced, how
many are expected to be tall and have yellow seeds?
8. Assume a male with type O blood mates with a female who has type A blood.
The female’s mother had type A blood and her father had type B. What is the
probability that their first child will have type A blood? What is the probability
that their third child will have type O blood?
9. In humans, one of the genes determining color vision is located on the X
chromosome.The dominant form (C) produces normal color vision; red-green
color blindness (c) is recessive. If a man with normal color vision marries a colorblind woman, what is the probability of their having a color-blind son?
A color-blind daughter?
10. In humans, normal color vision (C) dominates red-green colorblindness
(c). This is a sex-linked trait. Two parents produce daughters who are all
carriers and sons who are all normal. What are the probable genotypes of
the parents?
11. In the couple described in the last problem, the woman gives birth to a colorblind but otherwise normal daughter. The husband sues for a divorce on the
grounds of adultery. Will his case stand up in court? Explain.
12. In a species of Rabbit, the alleles for black (B) fur is dominant over, red
fur (r), which is dominant over yellow fur (y) , which is dominant over
white fur (w). What will the possible genotypes and phenotypes of the
offspring be if a Black heterozygote (Bw) and a red heterozygote (ry)
mated?
13. In the species of Rabbit above, a yellow rabbit and a red rabbit mate. 25%
of their offspring are white. What are the genotypes of the parents?