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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
cross-pollination 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 F1offspring. What would
the genotype and phenotype ratios be for the F2generation?
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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