Download Worksheet 19 - Iowa State University

BIO 313 Worksheet 19
Supplemental Instruction
Iowa State University
Leader:
Course:
Instructor:
Date:
Laura
Bio 313
Dr. Rodermel
12/2/15
Case Study Burmese Python
Parent 1:
Heterozygous for the extra large ventral (abdomen) scales (Ss). Therefore this parent does not
express the extra large scale trait. Heterozygous for the pigmentation trait (Pp). Therefore this parent
expresses the normal pigmentation.
Parent 2:
Heterozygous for the extra large ventral (abdomen) scales (Ss). Therefore this parent does not
express the extra large scale trait. Heterozygous for the pigmentation trait (Pp). Therefore this parent
expresses the normal pigmentation.
Questions:
1. Determine the possible genotype (s) that will produce individuals that have normal sized scales
(do not express the extra large abdominal scales) and have normal pigmentation (do not express
albinism). What is the frequency that each of these genotype (s) occur in the dihybrid cross?
2. Determine the possible genotype (s) that will produce individuals that have normal scales and are
albino? What is the frequency that each of these genotype(s) occur in the dihybrid cross?
3. Determine the possible genotype (s) that will produce individuals with extra large abdominal
scales and have normal pigmentation. What is the frequency that each of these genotype (s)
occur in the dihybrid cross?
4. Determine the possible genotypes that produce individuals with extra large scales and are albino?
Which of these genotypes occur in the dihybrid cross?
5. What is the ratio between the four phenotypic traits (normal scales with normal pigment,
albinism with normal scales, extra large scales with normal pigment, and albinism with extra large
scales).
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Case Study 2: Calico Cats
In cats, the gene for calico (multicolored) cats is codominant. Females that receive a B and an R
gene have black and oRange splotches on white coats. Males can only be black or orange, but never
calico.
Here’s what a calico female’s genotype would look like. X B X R
Show the cross of a female calico cat with a black male?
What percentage of the kittens will be black and male? _________
What percentage of the kittens will be calico and male? _________
What percentage of the kittens will be calico and female? _________
Show the cross of a female black cat, with a male orange cat.
What percentage of the kittens will be calico and female? _____
What color will all the male cats be? ______
Calico cats can also have two different eye colors: blue eyes (EE) are dominant to brown eyes (ee).
If the parents are XBXREe and XRYee what would be the potential offspring?
Dad with an X-linked recessive disorder crossed with a mom without the disorder in her immediate
family can produce the following offspring (maybe be more than one)
a. Males with the allele that show the trait
b. Females with the allele that show the trait
c. Females that don’t show the trait but are carriers
d. Females that don’t have the allele and don’t show the trait
e. Males that don’t have the allele and don’t show the trait
Male without an X-linked recessive disorder crossed with a female who has a dad with the disorder
can produce the following offspring (may be more than one)
a. Males with the allele that show the trait
b. Females with the allele that show the trait
c. Females that don’t show the trait but are carriers
d. Females that don’t have the allele and don’t show the trait
e. Males that don’t have the allele and don’t show the trait
True/False Quiz:
____ 1. At least one X is required for development of human males and females
____ 2. A single Y usually produces a male, regardless of the number of X’s
____ 3. A male can sometimes have XX sex chromosomes
____ 4. The absence of a Y usually produces a female
____ 5. 2 X’s are needed for female fertility; more X’s upset development (physical and mental
problems)
____ 6. A female can sometimes have XY sex chromosomes
____ 7. A person with XXXY sex chromosomes has Turner Syndrome
____ 8. Crossing over causes all the genetic variation seen in offspring produced by sexual
reproduction
____ 9. In humans, males are the heterogametic sex
____ 10. Butterfly females have ZW sex chromosomes