What combination(s) of chromosomes are possible in daughter cells following mitosis? Homework Help

1. (6 points) A diploid cell contains three pairs of homologous chromosomes
designated C1 and C2, M1 and M2, and S1 and S2. No crossing over occurs.
a. What combination(s) of chromosomes are possible in daughter cells following
mitosis?
In mitosis, two genetically identical daughter cells are produced. Therefore, the
only possible combination of chromosomes is C1/C2/M1/M2/S1/S2 since all
genetic material is inherited.
b. What combination(s) of chromosomes are possible in haploid cells following
both divisions of meiosis? (Hint: remember independent assortment)
C1/M1/S1, C1/M1/S2, C2/M1/S1, C1/M2/S1, C1/M2/S2, C2/M1/S1, C2/M2/S1
or C2/M2/S2.
2. (15 points) A recessive mutant allele, black, causes a very dark body in
Drosophila when homozygous. The normal wild-type color is gray.
a. A black female is crossed to a heterozygous gray male. What are the parental
genotypes?
b. What F1 phenotypic and genotypic ratios are produced from this cross? (Show
your Punnett Square)
3. (9 points) R codes for red flower color and r codes for white flower color.
a. What color would Rr be if R has complete dominance?
b. What color would Rr be if R and r are codominant?
c. What color would Rr be if R has incomplete dominance?

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4. (15 points) Red-green colorblindness is an X-linked recessive mutation. A
colorblind female is crossed with a normal male.
a. What are the parental genotypes? (Hint: the sex of the parent is important)

?SC435: Genetics

b. Diagram the F1 results from this cross. (Show your Punnett Square).
c. Diagram the F2 results. (Show your Punnett Square).
5.

(5 points) In a dihybrid cross between RrTt and RRtt, what are the genotype
and phenotype ratios of the offspring, assuming R and T are dominant? R
codes for round seed, while r codes for wrinkled seed. T codes for tall height,
while t codes for short height. (Show your Punnett Square).

6. (15 points) The pedigree below traces the inheritance of alkaptonuria, a
biochemical disorder. Affected individuals, indicated here by the filled-in circles
and squares, are unable to break down a substance called alkapton, which
colors the urine and stains body tissues.

a. Does alkaptonuria appear to be caused by a dominant or recessive allele?
Explain.
Alkaptonuria appears to be caused by a recessive allele because Ann and
Michael do not have the disorder but their child, Carla, does. Ann and
Michael must be carrying the recessive allele but it is masked by the
dominant one
b. What is George’s phenotype?
George is Aa, since some of his children with Arlene are affected
c. Is it possible for Daniel to have a child with alkaptonuria? Explain.
Yes Christopher can have the AA or Aa genotype.

?SC435: Genetics

d. How would knowing the pattern of inheritance influence the treatment plan
for this disease?
It would provide guidance to determine if genetic testing is appropriate.

7. (10 points) Mary has type A blood and her husband has type B blood. Her
husband’s parents both had type AB. They have three children, one with type A,
one with type AB, and one with type B. Relatives suspect that one of the children
was adopted.
a. What are the parent’s blood genotypes?

b. Which child was adopted? Explain your answer.

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