Problem Set #2 BioS 101 Spring 2010
10 possible points of credit
Due in Discussion on week 9, 9-12 March 2010
Students must email the completed problem set to their TA as an attachment. Include either 1) a statement of the logic used and/or steps taken (calculations if appropriate) in arriving at the answer, or (and) 2) the source of the information provided. Credit is conditional on satisfactory explanations. Put your answer with each question.
1. (1) a. How many different loci do you infer there are when you see the following genotypes?
A. HhMMOo _______
B. AbCe/abCE _______
C. PUSU/puSU _______
1b. For genotype A & B which loci are homozygous.
D. ________
E. __________
2. (1) The hypothesis is that the probability of an offspring being YELLOW is 0.75 and the probability of it being WHITE is 0.25, calculate the Chi-squared value of the observing 67 YELLOW and 33 WHITE peas? Do you accept or reject the hypothesis?
3. (1) There is a locus on the X chromosome of Drosophila called MINIATURE WINGS with the symbol M for the wild type allele and m for the miniature allele. That locus is 28 map units from the YELLOW BODY locus with the alleles YE & ye . If a YE M/ye m female undergoes meiosis what proportion of her gametes will have the YE m genotype?
4. (1) The common radish may be LONG ( RR ), ROUND ( Rr ) or OVAL ( rr ) in shape and its color maybe PURPLE ( PP ), RED ( Pp ), or WHITE ( pp ). The gene governing shape are not linked to the gene controlling color. What types of radish (and in what proportions) will result from a cross of a RED ROUND plant with a WHITE LONG one?
5. (1) List every different gametic genotype that could be formed by an individual with the aDg/AdG genotype (heterozygous at all 3 loci).
6. (1) Consider the aDg/AdG individual again. a. List the two gametic genotype(s) that are called parental (those that would result if there were no crossovers anywhere). b. List the gametic genotypes that would be produced if there was a crossover between the A and D loci. c. List the gametic genotypes that would be produced if there was a crossover between the A and D loci AND between the D and G loci.

7. (1) If you expect each pea to have a 0.75 chance of being YELLOW and a 0.25 chance of being GREEN, what percentage of the pods with 4 peas do you expect NOT to have 3
YELLOW peas and 1 GREEN pea? (Hint: You may find ‘not’ logic useful.)
8. (1) From a seed collected in the wild a plant with orange –spotted flower grew in the green house. The plant self pollinated and gave rise to the following progeny: 98 orangespotted, 33 yellow- spotted, 32 orange -no spots and 8 yellow –no spots.
A. What can you determine about the dominance relationship of the alleles at the spottedplain locus?
B. What can you determine about the dominance relationship of the alleles at the flower color locus?
C. What can you conclude about the genotype of the originally collected seed?
D. What can you conclude about the relationship of the two loci?
9. (1) A new wetland is established by mitigation laws. One hundred frogs are added to the wetland, 60 spotted and 40 plain, in 2002. The frogs of the wetland are inventoried in
2008. 220 spotted and 180 plain frogs are captured. What is the relative fitness of spotted to plain during this 6 year interval?
10. (1) All the members of a small island population of foxes have been genotyped at the
G & Q locus. The results are: GGqq Ggqq Ggqq ggQq ggqq Ggqq GGQq ggqq Ggqq
GgQq GGqq ggqq.
A. Calculate the frequency of the G allele
B. Calculate the frequency of the Q allele
C. Assuming random mating what is the expected frequency of the GGQQ genotype in the next generation?