Part I: Choose the one BEST answer. Circle its letter. Read each question and all 5 choices carefully because more than one answer might seem correct at first glance. 2 points each  

1. When sex chromosomes lack homology, the gender with two different (or only a single) sex chromosomes is
a. X-linked
b. always male
c. always female
d. hemizygous
e. heterozygous

2. The process of _____ is the source of new alleles
a. selection
b. mutation
c. polarity
d. meiosis
e. crossing over

3. Two genes do not exhibit linkage in dihybrid crosses if:
a. they are very far apart on the same chromosome
b. they are on different chromosomes
c. the recombinant frequency (RF) between them is > 0.5
d. a and b
e. all of the above

4. A kM/Km female that underwent one crossover event (between these two genes) during meiosis could produce which of the following gametes?
a. km and KM only
b. kM and Km only
c. Kk and Mm only
d. KM, Km, kM and km
e. K, k, M, and m

5. Two genes are known to be 53.8 map units apart. The expected percentage of nonparental (recombinant) offspring from a dihybrid testcross is:
a. 25%
b. 26.9%
c. 50%
d. 53.8%
e. not enough information given

6. A monohybrid cross (Dd x Dd) can illustrate Mendel's observations of:
a. dominance and recessiveness
b. random segregation
c. independent assortment
d. a and b
e. all of the above

7. DNA synthesis occurs
a. during interphase before meiosis
b. during interphase before mitosis
c. during prophase of mitosis
d. a and b
e. all of the a

8. A chromosome is made of
a. one piece of DNA with associated protein and RNA
b. euchromatin and heterochromatin
c. chromatin
d. a and b
e. all of the above

9. To determine the distance between three genes, a,b, and c,
a. only one dihybrid cross is necessary
b. two different dihybrid crosses are necessary: a - b and b - c
c. three dihybrid crosses are necessary: a-b, b-c, and a-c
d. each of these genes must be mapped with respect to a fourth gene, d
e. one cannot map three genes using dihybrid crosses

10. Given a cross between MmPPRrTtDdGG x MmPpRRTTDdGg, what is the chance of an offspring homozygous dominant at all of these loci?
a. 0
b. 1/4
c. 1/6
d. 1/64
e. 1/256

11. Two genes are known to be 5 map units apart. The expected percentage of nonparental (recombinant) offspring from a testcross is
a. 1%
b. 5%
c. 10%
d. 20%
e. not enough information given

12. A testcross is a cross in which
a. one parent is heterozygous at all loci under consideration
b. both parents are heterozygous at all loci under consideration
c. one parent is homozygous recessive (either male or female)
d. one parent's genotype is unknown
e. either c or d may be true

13. Given a cross between AaPPmmTtRRGg x AaPpmmTTRrGg, what is the chance of an offspring heterozygous at all of these loci?
a. 0
b. 1/6
c. 1/16
d. 1/32
e. 1/64

14. The term "wild type" indicates
a. the accepted "standard" strain of an organism, or allele of a gene (genotype or phenotype)
b. organisms out of control
c. organisms particularly prone to mutate
d. organisms found outside captivity
e. organisms which breed true

15.Which of the following cell types are capable of meiosis?
a. haploid
b. diploid
c. prokaryotic
d. eukaryotic
e. all of the above

16. In a monohybrid cross, the first filial generation will
a. all resemble the female parent
b. all resemble the male parent
c. all resemble the recessive parental type
d. all resemble the dominant parental type
e. resemble the dominant parental type more frequently than the recessive type, but not always

17. Given a cross between MmPPrrTtDdGg x MmPpRRTTDdgg, what is the chance of an offspring expressing the dominant phenotype for all six traits?
a. 0
b. 1
c. 9/32
d. (1/2)⁶
e. (3/4)⁶

18. A dihybrid cross (AaBb x AaBb) can illustrate Mendel's observations of:
a. parental equivalence
b. random segregation
c. independent assortment
d. a and b
e. all of the above

19. The term "wild type" indicates
a. organisms found outside captivity
b. organisms out of control
c. organisms particularly prone to mutate
d. the accepted "standard" strain of an organism, or allele of a gene (genotype or phenotype)
e. organisms which breed true

20. The rate of recombination between genes which are far apart on a chromosome should be fairly high, but observed recombination frequencies are often lower than expected because
a. an even number of crossovers results in a recombinant phenotype
b. an odd number of crossovers results in a recombinant phenotype
c. an even number of crossovers results in a nonrecombinant phenotype
d. an odd number of crossovers results in a nonrecombinant phenotype
e. none of the above affect observed recombinant frequencies.

Part II: Short answer 10 points each

1. What is the probability of:
a. tossing a fair coin and getting 4 heads in a row?   

b. pulling an ace (any of 4 aces) twice in a row from a complete 52 card deck?   

c. tossing two identical fair dice and getting a sum of 9?   

d. tossing two identical fair dice and getting a sum of 9 twice in a row? 

e. tossing two fair coins and getting heads on the quarter and on the penny the first time & tails on the quarter and on the penny the second time?  

Part III. Problems:

1. An individual known to be triply heterozygous was testcrossed to produce progeny with the following phenotypes. What were the phenotypes of the two parents? Map the genes. Your final answer should include the genotypes of both parents with the genes arranged in the correct order and in the correct allelic configuration (i.e. dominant and recessive alleles arranged properly on each chromosome). Map distances and interference must also be calculated. Place the completed maps in the upper right of the answer blank. DO NOT USE ANY OTHER PAPER.
 

2. The map of three genes is known. The first two are 16 map units apart, and the third is 8 map units further down. Starting with one purebred parental strain with the recessive phenotype at two of these loci (you can choose which two), and the other parental strain recessive at the third, show what organisms you would mate and what phenotypes you would expect in each generation in order to demonstrate [using 3-point mapping] the map of these three genes. Generate at least 1000 progeny for this project. 15 points  

3. Do the same thing as in problem # 2 using only dihybrid testcrosses to map the same genes. 10 points  

4. In exploring brave new worlds, you have come across a strange creature. Some have furry toes, while others have no fur on the toes; some have pointed and some have round ears, and some have four eyes while others have only three. Previous experiments indicate that each of these traits is governed by a single gene. Based on the following testcrosses, construct a map of these 3 genes, including the genotypes of all the parents in correct order & allelic arrangement, map distances, and interference. In addition, indicate the genotypes used for each testcross parent. 10 points

Extra credit 3 points: keep wild type & mutant information when you name the genes. Assume that most creatures have fury toes, pointed ears & four eyes.

Extra credit 2 points: calculate I