Please answer these questions on a separate sheet(s) of paper, and please type.Small, handwritten figures on an otherwise typed document are acceptable. It is imperative that no part of your answer be copied directly from an online source, or from another student, either in this class or from a previous year. This problem set is due at the beginning of discussion, the due date being listed on the syllabus.
1. A man who has type O blood fathers offspring with a woman who has type AB blood. Their first child, a girl, has type A blood.
a) Diagram this cross and include pedigree information as well.
b) What proportion of the gametes from the mother have the IA allele?
c) What would be the probability that their SECOND child, assuming they have one, will have type B blood?Diagram this cross as well and include pedigree information if needed to explain your conclusion.
2. A man and a woman walk into a genetic counselor’s office. The woman’s brother has recently been diagnosed with Duchenne muscular dystrophy. The man has no history of the illness in his family.
a) They are concerned about having an affected child themselves. The woman is pregnant with a girl. Diagram this cross. What is the chance that the child the woman carries will have the disorder?
b) If they have additional children, would a sperm or egg donor help to decrease the chance of an affected child?
3. A Drosophila melanogaster female with cinnabar eyes is crossed to a D. melanogaster male with brown eyes.The F1 are all red-eyed.
The F1 are allowed to cross with each other, and produce the following offspring.
57 red eyed
14 brown eyed
13 cinnabar eyed
6 white eyed
One of the white eyed females is cross with one of the male F1. The results are as follows
23 red eyes
27 brown eyes
25 cinnabar eyes
25 white eyes.
a) What genetic interaction is happening here? How many loci, how many alleles, and how do they interact?
b) Diagram both crosses and explain the results.
4. In horses, the chestnut/cream/palomino color is determined by having two recessive alleles at the extension locus. EE and Ee individuals are BLACK, ee individuals are chestnut/cream/palomino. Chestnut vs. cream vs. palamino color are determined by a second locus. CCHCCH individuals are chestnut, CCHCC individuals are palamino, CCCC individuals are cream. A black horse is crossed with another black horse. The resulting offspring is chestnut.
a) Diagram this cross. Is this incomplete dominance? Why or why not?
b) The two horses cross again. What is the chance that the second offspring will be chestnut as well?
5. A female Drosophila with red eyes is crossed with a male that has white eyes. Both lines are true-breeding.
a) Diagram this cross. What proportion of the F1 males, and females, are expected to have white eyes?
b) Imagine that the F1 progeny are allowed to cross and create an F2. Diagram this cross as well. What proportion of the F2 males would you expect to have white eyes?
6. A Drosophila melanogaster with tan body and red eyes, line A, is crosses with a D. melanogaster with a black body and cinnabar eyes, Line B. Both lines are true breeding. The resulting offspring are all tan bodied with red eyes. One of the F1 females is crossed with a male from line B. The resulting F2 offspring are as follows:
Tan body, red eyes 44
Tan body, cinnabar eyes 6
Black body, red eyes 8
Black body, cinnabar eyes 42
a) Are the two loci linked? What hypothesis do you implicitly test to find out? Do a chisquare test, cite your value and explain what it means.
bIf they are linked, how many map units apart are they?
c) What proportion of the gametes from the Line B males have the allele for black body and cinnabar eyes? What proportion of the gametes from the F1 males have the alleles for black body and cinnabar eyes?
7.Imagine that, in finches, beak depth is controlled by three genes, each of which has two alleles, a + allele and a – allele. The baseline depth is 6mm. Each + allele adds .5 mm to the depth of the beak, each – allele subtracts .1mmfrom the depth of the beak. Two finches with genotypes a+a-b+b-c+c- mate.
a) What is the beak depth, in mm, for each of the parents?
b) What is the probability that any given offspring from this cross will have a beak depth measuring 9mm or greater?
8. Refer to the pedigree below.
a) What type of trait is this
b) What is the genotype of Donna?
7. (Two points) Go to the following link and read the paper
http://www.nature.com/scitable/topicpage/rare-genetic-disorders-learning-about-genetic-disease-979
Write a two paragraph response to the paper, indicating what you have learned from reading it.