Problem Set 2
This problem set covers material from January 19
through January 26
From Griffiths et al.:
Chapter 2, problems 4, 8, 20, 22, 24, 28, 29, 30,
38, 39, 46, 47, 48,52, 53, 64
Chapter 6, problems 7, 8, 9, 12, 13, 14, 16, 23
Hand in answers to the following questions, due on February 4
You’re working on golden rice, a plant that promises to alleviate nutritional deficiencies in
some developing countries.
You cross two true breeding plants.
One parent has fat grains, wavy
leaves, red flowers and is short in stature, while the other parent expresses the contrasting
phenotypes of thin grains, straight leaves, white flowers and is tall in stature.
The four pairs of
contrasting traits are controlled by four genes, each located on a separate chromosome.
In the F
only fat grains, straight leaves, red flowers, and tall stature were expressed.
In the F
possible combinations of these traits were expressed in ratios consistent with Mendelian
(a) What conclusions can you draw about dominance relationships from the F1 results?
In the F
results, which phenotype appeared most frequently?
Calculate the probability of
this phenotype occurring.
(c) Which F
phenotype is expected to occur least frequently?
Calculate the probability of this
(d) In the F
generation, what is the probability of getting one or the other parental (p generation)
(e) If the F
plants were test crossed, how many different phenotypes would be produced?
does this number compare with the number of different phenotypes in the F
discussed in parts a-d?
Red-green color blindness is X-linked recessive.
A woman with normal color vision has a
father who is red-green color-blind.
The woman has four sons, none of whom are color-blind.
Assume everyone in the family has a normal complement of chromosomes.
Each of the next
three statements has an explanation for why none of the sons are color-blind.
For each, state if it
is possible or not possible, then give the reason for your choice.
i) None of the sons are color-blind because the mother does not carry the color-blindness allele.