Bio 115 – Lab 01 Genetics Review

| March 14, 2016

Question
Bio 115 On-line

Name:

Lab 01: Genetics Review (material from chapters 14 and 15)
This lab is designed to review Mendelian Genetics and Punnett Squares.
Complete the following questions. Type your answers in this Word document using a blue
colored type. Save the file with a name that includes your last name and the assignment title
such as: your last name_lab 01.docx. Submit your assignment to the appropriate Dropbox by
the specified due date.
For each scenario provide the following:
A) The genotype of each parent
B) Complete a Punnett Square
C) Record the genotype and phenotype of the offspring
D) Clearly answer each question of each scenario
1. In peas, round seed coats (R) is dominant over wrinkled seed coats (r). What will the
results be of a cross between a homozygous dominant male and a recessive female?
2. In peas, yellow color (Y) is dominant to green (y). What will be the results of a crosspollination of a heterozygous female and a heterozygous male?
3. In humans, straight toes (S) is dominant over curled toes (s). What would be the result of
a cross between a recessive male and a heterozygous female?
4. The ability to roll the tongue (R) is determined by a dominant gene while the recessive
gene results in the inability to roll the tongue (r). A man and his wife can both roll their
tongues and are surprised to find that their son cannot. Explain this by showing the
genotypes of all three persons.
5. In humans, wavy hair (CS) results by the co-dominant situation of curly hair (C) and
straight hair (S). What are the possible results if a curly-haired man and wavy-haired
woman have children?
6. In iris, purple (p) is incompletely dominant over white (w). What would be the results of a
cross if both parents were pale lavender (heterozygous-pw)?
7. In crocus flowers, white (W) and purple (P) colors are co-dominant, and result in a purple
and white striped flower when both genes are present. What are the possible results from
the cross-pollination of a striped crocus with a white crocus?
8. In cattle, red (r) is incompletely dominant over white (w) hides. Roan is the name of the
color that results from incomplete dominance. What are the possible results if a white male
mates with a roan female?

9. A heterozygous yellow, round pea is crossed to a homozygous green, wrinkled pea. What
is the likelihood of having fully homozygous offspring?
10. A disease is inherited as an autosomal dominant disease. A heterozygous male marries
a homozygous recessive female. What is the chance they will have an unaffected child?
11. Colorblindness is inherited as an X-linked recessive disease. An affected male marries a
heterozygous female. What is the chance that they will have an affected child? What
percent of their daughters will be affected? What percent of their sons will be affected?

12. Hairy ears are inherited as a Y-linked trait. A man with hairy ears marries a woman with
normal ears. What is the chance that they will have an affected child? What percent of their
daughters will be affected? What percent of their sons will be affected?
13. A disease is inherited as an X-linked dominant disease. An affected male marries an
unaffected female. What is the chance that they will have an affected child? What percent of
their daughters will be affected? What percent of their sons will be affected?
14. In Guinea pigs, black hair (B) is dominant over white (b), rough coat texture (R) is
dominant over smooth (r), and short hair (S) is dominant over long hair (s). Assuming these
genes are on separate chromosomes, draw the Punnett square for a cross between a
homozygous black, rough, short-haired Guinea pig and a white, smooth, long-haired one.
What would the phenotype(s) of the offspring be? Draw a Punnett square for a cross of the
F1 offspring. What would the genotype and phenotype ratios be for the F 2 generation?
15. A green-leafed hosta is crossed with a yellow-striped hosta. The cross produces a total
of 185 green-leafed offspring. Summarize the genotype and phenotype off the offspring and
the parents.
16. In dogs, there is hereditary deafness caused by a recessive gene “d”. A kennel owner
has a male dog that she wants to use for breeding purposes. Explain how you know the
male dog’s possible genotypes and describe a test to determine the actual genotype.
17. Mrs. Johnston, Mrs. Johnson, and Mrs. Johnstone all entered the same hospital and
gave birth to baby girls on the same day, and all three babies were taken to the nursery to
receive care. Someone later claimed that the hospital mixed up the babies. As a hospital
administrator, it is your job to make sure that each pair of parents has the correct baby, so
you order blood typing to be done on all the parents and all the babies. Use the blood
typing results to determine which baby belongs to each couple. Thoroughly explain your
logic.

Person

Blood Type

Mrs. Johnston

A+

Mr. Johnston

B+

Mrs. Johnson

B-

Mr. Johnson

O+

Mrs. Johnstone

A+

Mr. Johnstone

A-

Baby A

O+

Baby B

AB-

Baby C

B-

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