Tests from the Previous Semester
(Spring 1995)
General Genetics GB425
Emporia State University
These tests are provided as aids for your study so that you can become familiar with the types of questions that will be asked. Do not study only these old tests. New questions will be written each semester and old questions will be modified such that you must understand how to work the problems.
Last updated on 30 September 1995.
Provide comments to Dwight Moore at mooredwi@esumail.emporia.edu.
Return to the General Genetics Home Page at Emporia State University.
Genetics GB 425 Name
Spring 1995 Put your name on every page.
Exam #1
Circle the correct answer (3 points each)
1. The four stages of mitosis in order are:
a) anaphase, telophase, metaphase, prophase
b) prophase, metaphase, anaphase, telophase
c) telophase, anaphase, metaphase, prophase
d) metaphase, anaphase, telophase, prophase
2. During zygonema
a) the synaptonemal complex forms
b) terminalization of the chiasmata occurs
c) the spindle fibers attach to the centromeres
d) the chiasmata appear
3. Which of the following is the most likely outcome of a cross between a
heterozygous tall plant and a heterozygous tall plant?
a) 63 tall : 59 short
b) 76 tall : 23 short
c) 24 tall : 49 medium : 25 short
d) 53 tall : 147 short
4. Which of the following is a testcross?
a) AABB x AABB
b) AaBb X AaBb
c) AaBb x AABB
d) aabb X AaBb
5. Given 4 loci with 2 alleles at each locus, how many different gametic
genotypes are possible?
a) 16
b) 8
c) 81
d) 4
6. In fruit flies, the gene that is called the sex-switch gene is
a) doublesex
b) zinc finger gene
c) sex lethal
d) songless
7. In fruit flies, the theory that predicts the sex of flies is
a) the genic balance theory
b) the chromosome theory
c) the segregation theory
d) the cell theory
e) the numerator/denominator theory
8. If 83 individuals are homozygous for the recessive trait, eyeless, and 67
of the individuals are eyeless, then this is an example of
a) expressivity
b) pleiotropy
c) incomplete penetrance
d) incomplete dominance
9. Which of the following modes of inheritance would have the highest
frequency of expression for a rare trait in a family pedigree.
a) Z-linked recessive
b) autosomal dominant
c) X-linked recessive
d) autosomal recessive
10. If the level of significance (alpha) is set at 0.10, the chance of
rejecting a true null hypothesis is
a) 0.90
b) 0.05
c) 0.45
d) 0.10
11. The proteinaceous complex that forms between homologous pairs of
chromosomes during prophase I is called
a) collagen
b) the synaptonemal complex
c) the chiasmata
d) the kinetochore
12. If a corn snake has a diploid number of 24 chromosomes, how many
chromatids are in a cell during prophase of mitosis
a) 24
b) 48
c) 12
d) 96
e) 60
13. The structure that indicates that crossing-over has occurred is
a) centromere
b) synaptonemal complex
c) chiasmata
d) kinetochore
14. After S phase a chromosome exists as
a) a pair of sister chromatids with one centromere
b) a pair of homologous chromosomes
c) a pair of sister chromatids with two centromeres
d) a single chromatid with one centromere
15. In a cross between two black labrador retrievers the phenotypic ratio of
the offspring is 9 black puppies to 3 chocolate puppies to 4 yellow puppies;
this is an example of
a) partial recessiveness
b) incomplete penetrance
c) incomplete dominance
d) epistasis
16. Which of the following concepts is attributable to Sutton and Boveri?
a) one allele may be dominant to another allele at the same locus
b) chromosomes are the carriers of the genes
c) genetic traits are particulate in nature
d) the pair of alleles at a locus separate from each other during gamete
formation
17. In a cross between a black-skinned individual and a white-skinned
individual the children will be intermediate in color (tan); this is an
example of
a) partial recessiveness
b) incomplete penetrance
c) incomplete dominance
d) epistasis
18. If an affected male has affected daughters and sons in about the same
number as unaffected daughters and sons, the trait is likely to be an
a) X-linked dominant trait
b) autosomal recessive trait
c) autosomal dominant trait
d) X-linked recessive trait
19. Breast development in mammals is only seen in mammalian females and the
trait is inherited on the autosomes. This is an example of a
a) Y-linked trait
b) X-linked trait
c) sex-influenced trait
d) sex-limited trait
20. For the pedigree above, which mode of inheritance is most likely true
a) X-linked dominant
b) Y-linked
c) autosomal dominant
d) autosomal recessive 21. The null hypothesis is stated in such away that
a) the observed and expected distribution are different
b) the observed and expected distribution are the same
c) the means of the two groups are different
d) it is similar to the alternate hypothesis
22. In doing a chi-square test on the results of a trihybrid cross, the
number of degrees of freedom would be
a) 16
b) 7
c) 15
d) 3
e) 1
23. Given a cross between an individual who is heterozygous for brown eyes
and a person who is homozygous for blue eyes, what is the probability of
having 2 blue-eyed children out of 5 total children.
a) 0.4219
b) 0.0625
c) 0.3125
d) 0.5000
Compare and contrast (5pt each)
Compare means to tell how the two things are similar and contrast means to
tell how the two items are different. To simply give a definition for each
item is not an appropriate answer.
null hypothesis vs alternate hypothesis
sex chromosome vs autosome
Essays questions (10pts)
1. Compare the mechanism of sex determination for fruit flies to the
mechanism of sex determination for humans.
2. Explain how the rule of independent assortment allows you to predict the
outcome of a cross between two individuals both with a genotype of RrYy.
Genetics GB 425 Name
Spring 1995 Put your name on every page.
Exam #2
Circle the correct answer (3 points each)
1. The following mouse-human hybrid cell lines have the human chromosomes as
shown in the first table and the human enzymes as shown in the second table.
human chromosome
clone 3 7 9 11 15 18 20
X - - - + + + +
Y + + - + - + -
Z - + + - - + +
clone
X Y Z
glutathione reductase + + -
malate dehydrogenase + - -
galactokinase - + +
Which chromosome is the carrier of galactokinase?
a) 3
b) 18
c) 7
d) 11
2. A heterozygous fly with a wildtype phenotype is testcrossed and the
following progeny are produced;
groucho- 518; rough- 471; groucho, rough- 6; wildtype- 5
Which flies represent nonrecombinants?
a) groucho
b) wildtype
c) rough
d) groucho, rough
e) c & d
f) a & b
g) a & c
3. A lod score is a
a) measure of the interference of one crossover with another
b) measure of genetic diversity in a population
c) measure of the probability of linkage between two loci
d) measure of the number of human chromosomes in an hybrid cell
4. Which of the following cells is a prototroph?
a) his+met+pro+
b) his-met+lys+
c) glu-try-lys-
d) thy+met-lys+
5. The bacterial genome exists as
a) several circular pieces of DNA with many proteins attached
b) several long strands of DNA
c) a single long strand of essentially naked DNA
d) a circular piece of essentially naked DNA
6. The process by which a bacterial cell picks up exogenous pieces of DNA
and incorporates it into its genome is called
a) conjugation
b) transformation
c) transduction
d) translocation
7. If an individual is heterozygous for a paracentric inversion, we would
expect a
a) 33% reduction in fertility
b) 50% reduction in fertility
c) 25% reduction in fertility
d) 66% reduction in fertility
8. A human with Turner's syndrome would represent
a) a diploid condition
b) a euploid condition
c) an aneuploid condition
d) a trisomic condition
9. In a cross between F1s, it is found that the extreme phenotype occurs
about 1 out of every 4000 offspring. The number of loci that control this
trait is
a) 2
b) 5
c) 4
d) 6
e) 3
10. A technique for identifying individual chromosomes in a cell is
a) giemsa staining
b) inversion analysis
c) S-banding
d) G-banding
11. In a transformation experiment in which the a+b+ strain is the donor to
the ab strain, the following transformant were recovered: a+b = 45, ab+
= 25, a+b+ = 210. The distance between the a locus and the b locus is
a) 33
b) 50
c) 25
d) too far apart to calculate
12. A coefficient of coincidence is
a) measure of the interference of one crossover with another
b) measure of the probability of linkage between two loci
c) measure of the number of human chromosomes in an hybrid cell
d) measure of genetic diversity in a population
13. If an individual is heterozygous for a reciprocal translocation, we
would expect a
a) 33% reduction in fertility
b) 50% reduction in fertility
c) 25% reduction in fertility
d) 66% reduction in fertility
14. A heterozygous trihybrid corn plant is testcrossed and the following
progeny are produced (all traits are recessive to their wildtype
alternative);
booster 6
booster, silkless 137
booster, liguleless, silkless 291
liguleless 142
liguleless, silkless 3
silkless 30
booster, liguleless 34
wildtype 339
What is the order of the loci on the chromosome
a) liguleless, booster, silkless
b) booster, silkless, liguleless
c) silkless, liguleless, booster
d) liguleless, silkless, booster
15. Because of a translocation involving non-homologous chromosomes, a
growth gene suddenly finds itself expressed at a much higher rate and the
cell becomes cancerous. This activation of the growth gene is because of
a) suppression of crossing over
b) nullisomy
c) transduction
d) position effects
16. Two percentage of recombination equals a distance between the loci of
a) 200 map units
b) 2 centimorgans
c) 200 centimorgans
d) 20 map units
17. cv 9 m.u. st 18 m.u. lx
If we have a chromosome with three loci in which the distance between loci is
as indicated, then the probability of a double cross-over is
a) 0.900
b) 0.016
c) 0.180
d) 0.081
18. The occurrence of tetratype tetrads in the ascomycete fungi could only
occur if crossing over occurred during
a) the four strand stage
b) during G1 phase
c) the two strand stage
d) during S phase
19. Individuals made up of cells with different numbers of chromosomes
(mosaics) are caused by
a) nondisjunction during mitosis
b) interference during crossing over
c) failure of a chromosome to replicate during S phase
d) nondisjunction during meiosis
20. At a single locus with two alleles ("S" and "s"), if the frequency of
the "S" allele is 0.640 in a population, then the frequency of the "s" allele
is
a) 0.640
b) 0.360
c) 0.180
d) 0.800
21. Which of the following individuals will have the MOST trouble in
producing functional gametes during meiosis?
a) triploid with 30 total chromosomes
b) tetraploid with 48 total chromosomes
c) tetraploid with 12 total chromosomes
d) diploid with 46 total chromosomes
22. The conversion of a diploid karyotype of 8 acrocentric chromosomes to a
diploid karyotype of 4 metacentric chromosomes would be due to
a) polyploidy
b) deletions
c) translocations
d) centric fusions
23. In a sample from a population there were 85 individuals with the "BB"
genotype, 30 individuals with the "Bb" genotype, and 10 individuals with the
"bb" genotype. The frequency of the "b" allele was
a) 0.68
b) 0.58
c) 0.32
d) 0.08
Essay questions (10pts)
essay #1. Even though the X chromosome is a large chromosome, several
trisomic conditions of the X are known to have survived to birth, however, no
trisomic condition for the other large chromosomes (autosomes) have been know
to survive to birth. Explain why?
essay #2. The following three recessive markers are known in lab mice; h,
hotfoot; o, obese; and wa, waved. A trihybrid of unknown origin is
testcrossed to produce the following offspring:
hotfoot, obese, waved 345
hotfoot, obese 87
waved 66
hotfoot 8
obese 83
wildtype 341
hotfoot, waved 60
obese, waved 10
Determine the gene order and explain your procedure. Then calculate the map
distance between the loci (show your work).
essay #3. Diagram a pedigree with at least 10 children in the 3rd generation
that indicates linkage between two loci with a 10% rate of recombination. Be
sure to define the loci and to indicate the children that are recombinants.
Set-up the equation(s) for the calculation of a lod score.
Genetics GB 425 Name
Spring 1995 Put your name on every page.
Exam #3
Circle the correct answer (3 points each)
1. Given 1 locus with 2 alleles that are strictly additive, the additive
genetic variance (2pqa2) is at a maximum when
a) q = 0.5
b) q = 1.0
c) q = 0.0
d) p = 0.25
2. Given that G = 0.50, E1 = 0.10, and E2 = 0.40, which of the following
pairs of individuals will be most similar in ability to score high on an IQ
test.
a) siblings reared apart
b) grandson - grandfather
c) dizygotic twins reared together
d) monozygotic twins reared apart
3. In a population of flies the mean bristle number was 6.4. Three pairs of
flies were used as parents and their mean bristle number was 7.2. Their
offspring had a mean bristle number of 7.0. What was the realized
heritability?
a) 0.75 b) 0.25 c) 0.91 d) 0.86
4. A measure of dispersion about the mean in a population is the
a) covariance
b) average
c) correlation
d) variance
5. Which of the following populations has the highest phenotypic variance
for flower color?
a) F=0, all individuals are homozygous for red flower color.
b) F=1, half of the flowers are red and half are white.
c) F=0, half of the flowers are pink, the others red or white.
d) F=1, 80% are red and 20% are white.
6. Disassortative mating would act to
a) change the allele frequency
b) increase heterozygosity
c) decrease heterozygosity
d) remove the dominant allele from the population
7. Which of the following is an assumption for Hardy-Weinberg equilibrium?
a) no epistasis
b) no dominance
c) no crossing-over
d) no mutation
8. Inbreeding would act to
a) change the allele frequency
b) increase heterozygosity
c) decrease heterozygosity
d) remove the dominant allele from the population
9. If the frequency of the "AA" genotype is 0.50 and
the frequency of the
"Aa" genotype is 0.30 in a population, then under Hardy-Weinberg, the
frequency of matings between the "aa" and "aa" genotypes would be
a) 0.063
b) 0.250
c) 0.040
d) 0.150
10. If the frequency of the "AA" genotype is 0.30 and the frequency of the
"aa" genotype is 0.20 in a population, then the frequency of the "Aa"
genotype is
a) 0.25
b) 0.20
c) 0.30
d) 0.50
11. At a single locus with two alleles ("S" and "s"), if the frequency of
the "S" allele is 0.360 in a population, then the frequency of the "s" allele
is
a) 0.640
b) 0.180
c) 0.800
d) 0.360
12. Disruptive selection with random mating among the phenotypes would
result in
a) a shift in the population mean
b) two new species
c) a decrease in the population variance
d) a bimodal distribution for the phenotype
13. The frequency of children homozygous for the recessive allele for cystic
fibrosis is about 0.0009. What is the frequency of heterozygotes in the
population?
a) 0.03
b) 0.97
c) 0.06
d) 0.94
14. The frequency of "A" in the population is 0.7 and the frequency of "a"
is 0.3. The frequency of the "Aa" genotype is 0.32. What is the inbreeding
coefficient for the population?
a) 0.32
b) 0.24
c) 0.76
d) 0.68
15. The overall effect of migration between two populations is to
a) increase the outbreeding within the populations
b) increase the similarity between the populations
c) increase the inbreeding within the populations
d) decrease the similarity between the populations
16. A male red-winged blackbird that can control a larger territory and thus
obtains more copulations with females is an example of
a) stabilizing selection
b) fecundity selection
c) sexual selection
d) zygotic selection
17. Given that 100 individuals of the most fit genotype produce 1000
offspring, then the relative fitness of a genotype for which 100 individuals
produce 600 offspring is
a) 0.85
b) 1.00
c) 0.60
d) 0.15
18. We have a population of fence lizards (Sceloporus) that have been living
on an island off the coast of North Carolina and unable to cross to the
mainland for many thousands of years. The frequency of allele "a" at locus
A in this population was 0.50. The frequency of allele "a" in the mainland
population is 0.30. A few years ago humans built a bridge to this island and
occasionally a lizard scurries across to the island from the mainland and
mates. Today the frequency of "a" in the island population is 0.45. What
has been the total extent of migration (m) since the bridge was built.
a) 0.25
b) 0.30
c) 0.05
d) 0.20
19. Consider a locus with alleles "A" and "a" at which "A" mutates to "a" at
the rate of 6x10-5 and "a" mutates to "A" at the rate of 7x10-6. What is the
equilibrium value of q?
a) 0.104 b) 0.896 c) 0.117 d) 0.883
20. In the t-allele system, males that are heterozygous for the "t" allele
produce gametes such that 95% carry the "t" allele; this is an example of
a) gametic selection
b) directional selection
c) disruptive selection
d) fecundity selection
21. A selection model in which the heterozygote has the highest fitness
results in
a) both alleles maintained in the population in a stable equilibrium
b) both alleles maintained in the population in an unstable equilibrium
c) the allele associated with the most fit homozygote replaces the other
allele
d) the most common allele replaces the other allele.
22. Which of the following scientists were part of the Neo-Darwinist
movement?
a) Mendel b) Darwin
c) Lamarck d) Fisher
23. Which scientist was the first to recognize that variation in natural
populations was important to explain the biology of the population?
a) Mendel b) Darwin
c) Lamarck d) Fisher
Essay questions (10pts)
1. Describe (define) the additive genetic variance and discuss the role that
the additive genetic variance plays in a population's response to selection.
2. Describe the concept of genetic drift and explain how this relates to the
concepts of bottlenecks and founder effects.
3. Given the following numbers of genotypes, a) calculate the frequency of
each allele, b) calculate the expected frequency for each genotype, c)
calculate the expected numbers for each genotype, and d) test for
Hardy-Weinberg equilibrium. The critical chi-square value is 3.814.
AA Aa aa
observed numbers 25 55 10
Last updated on 30 September 1995.
Provide comments to Dwight Moore at mooredwi@esumail.emporia.edu.
Return to the General Genetics Home Page at Emporia State University.