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1
Q

A mutation that changes the codon UAA to the codon UAG in a mammalian cell line is called a(n)

A

synonymous mutation

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2
Q

A mutation changes a codon from AAA (encoding lysine) to AGA (encoding arginine) in yeast, but no mutant phenotype is detected when the mutant strain is plated and grown on minimal or complete medium. This type of mutation is called

A

missense

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3
Q

A mutation does not affect the length of a gene but results in an abnormally short protein. The mutation is most likely of a type called

A

nonsense

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4
Q

A small (one-base-pair) insertion in the middle of the coding region of a gene will cause a

A

frameshift mutation

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5
Q

A point mutation in a gene’s promoter will most likely cause the production of

A

reduced amounts of mRNA and protein

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6
Q

The rare enol form of thymine pairs with guanine. If a thymine enolization occurs during replication, what would be the mutational event?

A

TA to CG

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7
Q

After mutagen treatment, a molecule of 2-aminopurine (an adenine analogue) incorporates into DNA. During replication, the 2-AP protonates. The mutational event caused by this will be

A

AT to GC

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8
Q

During mutagenic treatment with nitrous acid, an adenine deaminates to form hypoxanthine, which bonds like guanine. The mutational event would be

A

AT to GC

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9
Q

Which mutagen causes transitions (usually GC to AT) by adding an alkyl group to a base (usually G), thus altering its pairing properties?

A

ethymethanesulfonate (EMS)

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10
Q

Which mutagen causes AT-to-GC transitions by acting as a base analog for adenine? Hint: It is unstable and readily undergoes tautomeric shifts. Its imino form pairs with C rather than G.

A

2 aminopurine

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11
Q

Which of the following scientists discovered the Ac and Ds transposable elements in maize?

A

babara McClintock

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12
Q

A corn plant is homozygous for a mutant allele that results in no pigment in the seed (i.e., white). The mutant is caused by Ds insertion that often exits late in seed development, when there is an active Ac element in the genome. The seeds of this plant will be

A

white with small spots of pigment

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13
Q

Which of the following features do bacterial and corn transposons not have in common?

A

both may carry drug resistance genes in natural population

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14
Q

an autonomous element

A

requires no other elements for its mobility

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15
Q

Retrotransposons move via an intermediate that is

A

single-stranded RNA

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16
Q

LINEs differ from retrotransposons in that LINEs do NOT

A

contain LTRs

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17
Q

What percentage of the human genome is derived from transposable elements?

A

50%

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18
Q

A particular hybrid species is defined as 3n = 12. It is discovered that at meiosis, pairing is always univalent + bivalent (never trivalent) in this species. How many bivalents will be present in prophase of meiosis I?

A

4

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19
Q

For autosomes in diploid organisms, the aneuploid 2n + 1 is

A

trisomic

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20
Q

for autosomes in diploid organisms, the aneuploid 2n-1 is

A

monosomic

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21
Q

For autosomes in diploid organisms, the aneuploid 2n – 2 is

A

nullisomic

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22
Q

A man is found to be karyotypically 47, XYY. The presence of an extra Y chromosome most likely results from

A

Nondisjunction in a paternal meiocyte at meiosis II.

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23
Q

A hybrid allotetraploid species (2n = 60) was backcrossed to one of the suspected parents (2n = 30). When the F1 underwent meiosis, the prophase chromosome configuration was examined. If the guess about the suspected parent was correct, what would the chromosome configuration look like?

A

15 pairs and 15 singles

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24
Q

The red fox has 17 pairs of large, long chromosomes. The arctic fox has 26 pairs of smaller shorter chromosomes. What do you expect to be the chromosome number in somatic tissues of a red fox/arctic fox hybrid?

A

43

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25
Q

spontaneous mutations

A

“background” mutation rate. Influence phenotype occurs at a very low rate

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26
Q

induced mutations

A

caused by muta gens= agents that increase the rate of mutations. can occur at a high rate.

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27
Q

men are

A

4 times more likely to have mutations.

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28
Q

point mutations

A

mutations that map to a single and specific point(usually a single base pair or a few base pairs)

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29
Q

Indels

A

insertion or deletions

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30
Q

depurination

A

occurs spontaneously all the time

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31
Q

deamination

A

Removal of an amino group from a base. This most commonly occurs at cytosine.

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32
Q

transposable genetic elements

A

DNA sequences can move within the genome through an enzyme-driven process called transposition.

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33
Q

insertion inactivation

A

a transposable element can cause a mutation if it inserts into a wild-type allele and disrupts its function

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34
Q

dissociation (Ds) element

A

is the location of chromosome breakage.

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35
Q

Activator (Ac) element

A

Ds can not cause chromosome breakage without this second element.

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36
Q

McClintock concluded that the unstable mutant alleles

A

were cause by insertion of Ds into the C locus to produce a kernel lacking pigmentation

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37
Q

why does the insertion of Ds into the C locus cause the colorless phenotype?

A

the insertion mutates the allele and disrupts its original function of producing blue pigment

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38
Q

transposition requires what enzyme?

A

transposase

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39
Q

autonomous transposable elements

A

carry a transposase gene and all DNA sequences needed to carry out transposition

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40
Q

non-autonomous transposable elements

A

have no transposase gene and may lack the sequences need for transposition

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41
Q

IS (insertion sequence) elements

A

are simple transposable elements containing only the genes and sequences needed for autonomous transposition.

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42
Q

Bacteria has how many types of transposons

A

two

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43
Q

composite transposons

A

have a central region of several kb containing one or more functional genes.

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44
Q

simple transposons

A

are flanked bby very short IR sequences of less than 50bp

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45
Q

DNA transposons

A

are transposed through conservative or replicative transposition (DNA cut and paste)

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46
Q

retrotransposons

A

are transcribed then reverse transcriptase produces a double-stranded DNA copy of the element, which is then inserted into the genome. (copy and paste)

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47
Q

what virus is a retrovirus

A

HIV

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48
Q

what is the ploidy of strawberry

A

4n

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49
Q

what is the ploidy of bread wheat?

A

6n

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50
Q

what is the ploidy of seedless watermelon

A

3n

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51
Q

Meisosis in even numbered eukaryotes

A

works because of the need to pair with homologs

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52
Q

Meiosis in odd number

A

fails because chromosomes will not pair with a homolog

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53
Q

Autopolypoidy

A

occurs when organisms have more then two sets of chromosomes from the same species

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53
Q

allopolyploidy

A

when organism contain two or more sets of chromosomes that are form different species.

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53
Q

why does triploidy not work?

A

because gametes with one or two of each chromosome will produce inviable offspring.

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53
Q

monosomic

A

missing one copy of one chormosome (2n-1)

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54
Q

trisomic

A

an additional copy of one chromosome (2n+)

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55
Q

nullisomic

A

no copies of a particular chromosome (2n-2)

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56
Q

translocations

A

Chromosomal breakage followed by reattachment of the broken segment to a non homologous chromosome.

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57
Q

where does heritable genetic variation come from?

A

mutation

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58
Q

microsatellite markers

A
  • high mutation rate, multiple alleles at the same locus, tandem repeats, highly abundant in genomes
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59
Q

what is a population?

A

a group of interbreeding organisms

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60
Q

what is a gene pool

A

the collection of genes and alleles found in the members of a population

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61
Q

Hardy-Weinburg equilibrium

A

serves as a model to calculate the frequencies of alleles and genotypes in a population that is infinitely large, practices random mating, and does not experience evolutionary change. alleles and genotype frequencies remain constant.

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62
Q

p^2=

A

A1xA1

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63
Q

2pq=

A

2(A1xA2)

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64
Q

q^2=

A

A2xA2

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65
Q

mutation _____ genetic diversity

A

increases

66
Q

migration _____ genetic diversity

A

increases

67
Q

genetic drift _____ genetic diversity

A

decreases

68
Q

the effect of genetic drift is stringer in _____ population

A

small

69
Q

what does natural selection favor?

A

reproductive fitness

70
Q

relative fitness

A

high reproductive success

71
Q

directional natural selection

A

one phenotype has a higher relative fitness than other phenotypes. increase the frequency of the favored allele over the others.

72
Q

directional selection ____ genetic diversity

A

decreases

73
Q

balanced polymorphism

A

allele frequencies are maintained by selection against either homozygote

74
Q

inbreeding

A

is mating between related individuals

75
Q

inbreeding ____ genetic diversity

A

decreases

76
Q

discontinuous variation

A

displayed by phenotypes of single-gene traits

77
Q

continuous variation

A

what polygenic and multifactorial traits are controlled by many genes and show

78
Q

how many genetic variants (SNPs) affect human height

A

10000

79
Q

major gene

A

several alleles that strongly influence something

80
Q

modifier genes

A

influence genes to a lesser degree.

81
Q

additive genes

A

a gene in which there are neither dominant nor recessive alleles, although gradations may exist between extremes.

82
Q

additive trait

A

more alleles associated with a particular trait an individual possesses, the greater the expression of that trait.

83
Q

multiple gene hypothesis

A

in the early 1900s, geneticists began to investigate the idea that segregation of alleles of multiple genes played a role in phenotypic variation.

84
Q

no gene-environment interaction

A

each genotype corresponds to a discrete phenotype

85
Q

moderate gene-environment interaction

A

minor overlaps between phenotypes in the F2

86
Q

substantial gene-environment interaction

A

wide phenotypic ranges and significant overlap

87
Q

threshold traits

A

There is constant variation of phenotypes, but the phenotypes can still be divided into distinct categories, either affected or unaffected.

88
Q

frequency distribution

A

shows the proportion of individuals for each category

89
Q

varience (s^2)

A

is a measure of the spread of distribution around the mean

90
Q

variance equation

A

s^2=E(xi-x)^2/df

91
Q

standard deviation

A

expresses deviation from the mean in the same units as the scale of measurement for the sample s=√s^2

92
Q

phenotypic variance

A

Vp=Vg+Ve

93
Q

genetic variance

A

Vg, is the proportion of phenotypic variance due to genotypes differences.

94
Q

environmental variance

A

Ve

95
Q

in highly inbred mice populations where all individuals are homozygous for alleles controlling a trait, what is the genetic variance for this trait?

A

Vg is 0

96
Q

we keep a population of maize in the same lab environment and measure their heights. what is the environmental variance

A

Ve is 0

97
Q

additive variance

A

Va, derives from the added effects of all alleles contributing to the trait

98
Q

dominance variance

A

Vd, results from dominance relationships in which heterozygous individuals are not intermediate between the two homozygous states

99
Q

interactive variance

A

Vi, derives from epistatic interactions between alleles contributing to a trait

100
Q

concept of heritability

A

was developed to help measure the proportion of phenotypic variation that is due to genetic variation

101
Q

broad sense of heritability

A

H^2=Vg/Vp, estimates the proportion of phenotypic variation that is due to total genetic variation

101
Q

Narrow sense of heritability h^2

A

h^2=Va/Vp, estimates the proportion of phenotypic variation that is due to additive genetic variability

102
Q

selection differential

A

S, the difference between the means of the whole population and the breeding population

103
Q

response to selection

A

R=Sxh^2, depends on the extent to which the difference between the population mean and the mean of the mating individuals can be passed on to progeny

104
Q

h^2

A

=R/S

105
Q

An animal breeder asks for your advice about which of a number of traits could most effectively be selected for his herd. which would you most correctly suggest?

A

a high Va relative to Vp

106
Q

which of the following is most typical of a case of quantitative inheritance

A

continuous variation in phenotypes

107
Q

A high variance indicates that

A

the variation among the values is high.

108
Q

Which of the following statements is/are a central assumption of the multifactorial inheritance hypothesis?

A

Several loci are associated with the trait.

109
Q

The amount of milk produced per day by a cow is an example of a

A

continuous trait

110
Q

A large number of genetically identical tomato plants are grown in a greenhouse. The mean height in this plant population is 84 cm, and the standard deviation is 2.5 cm. The variation in height within this population is most likely due to

A

differences in the plants’ microenvironment.

111
Q

When all of the variation in a population is due to environmental sources and there is no genetic variation, broad-sense heritability (H2) is

A

zero and all of the phenotypic variability is due to environment.

112
Q

A quantitative geneticist measures the broad-sense heritability for bill length in an isolated population of ducks to be 0.75. This result suggests that

A

in the population tested, 75% of the variance in bill length is due to genetic differences among individuals.

113
Q

Narrow-sense heritability (h2) is a quantification of the proportion of total variance due to

A

additive genetic variance

114
Q

what is a species

A

a collection of organisms that can interbreed and produce fertile offspring

115
Q

what is a population

A

a group of organisms that live in a defined area and can interbreed

116
Q

what is phenotypic variation

A

the variability in phenotypes that exists in a population

117
Q

what is selection pressure

A

impact on a trait from a population’s environment from human activity or from other organisms.

118
Q

what is fitness

A

the ability to survive to reproductive age, find a mate, and produce offspring

119
Q

survival of the fittest

A

term that suggests that organism best adjusted to their environment are the most successful in surviving and reproducing

120
Q

what is adaptation

A

modification of an organism or its parts that make it more fit

121
Q

what is biological evolution

A

change of allele frequency in populations

122
Q

does the gene that encodes lactase present in juvenile mammals disappear when they grow older?

A

No, the cell just stops expressing that gene by stoping transcription of that DNA.

123
Q

missense muation

A

nonsynonymous but changes amino acid

124
Q

silent mutation

A

synonymous mutation but does not change amino acid

125
Q

nonsense mutation

A

forms new stop codon

126
Q

keto and enols form pairs with

A

different nucleotides

127
Q

depurination

A

removal of purine from apurinic site an then replaced with other purine

128
Q

deamination

A

removal of an amino group from a base

129
Q

what are the effects of the muattions induced by mutagens

A

they are harmful

130
Q

what do inversions do?

A

they supress the production of recombinant chromosomes because they are not viable if crossover occurs in the inversion loop.

131
Q

larger inversion =

A

lower fertility and higher probability of crossing over in the loop.

132
Q

inversion loops result in

A

major chromosomal deletions after recombination in an inversion heterozygote

133
Q

as long as genes or regulatory regions are away from the breaking point

A

the inversions and translocations will likely not have phenotypic consequences (except for reduced fertility)

134
Q

Which of the following processes will increase genetic variation within populations?

A

mutation

135
Q

Which of the following are requirements for evolution by natural selection?

A

differential survival and reproduction, heritability of phenotypic variation, and variation in phenotype

136
Q

Which of these principles of evolution, as described by Darwin’s theory, is correctly matched with its role in evolution?

A

Principle of variation: Variation in morphology, physiology, and behavior must be present in a population for selection to occur.

137
Q

Which of the following is/are NOT a principle of Darwinian evolution?

A

Darwinian evolution fully describes where all living things come from.

138
Q

Which of the following reduce heterozygosity?

A

directional selection

139
Q

how might a single base insertion into the second codon of the coding sequence of a gene affect the amino acid sequence of a protein encoded by the gene?

A

the amino acid sequence would be altered.

140
Q

which type of mutation converts a nucleotide to an alternative structure with same composition but a slightly different placement of rare, less stable hydrogen bonds that cause base-pair mismatch?

A

tautomeric shift

141
Q

An intercalating agent such as aflatoxin is more likely to cause which type of mutation?

A

frameshift

142
Q

which of the following statements is true of non-homologous end joining?

A

it is a double-strand repair pathway, and it is error prone

143
Q

nucleotide base repair

A

using undamaged strand as a template to repair the damaged strand.

144
Q

in an allopolyploid organism, what is true regarding the fertility of interspecies hybrids?

A

chromosome doubling and nondisjunction in gametocytes can lead to homologous chromosome pairing, disjunction, and fertile hybrids.

145
Q

heterozygous carriers of chromosome inversions or translocations____.

A

may or may not exhibit phenotypic abnormalities, and may be infertile due to complications during meiosis

146
Q

A region of a chromosome spanning the centromere is broken and reattached in the reverse direction. This is an example of which type of chromosomal defect?

A

pericentric inversion

147
Q

a chromosome has broken, and a piece of one chromosome is translocated to a non-homologous chromosome. this is an example of what type of chromosomal alteration?

A

unbalanced translocation

148
Q

Alu1 is an example of which type of transposable element commonly found in the genome of humans?

A

SINE elements

149
Q

LINE elements

A

a group of non-LTR (long terminal repeat) retrotransposons that are widespread in the genome of many eukaryotes.

150
Q

SINE elements

A

a class of retrotransposons, DNA elements that amplify themselves throughout eukaryotic genomes, often through RNA intermediates.

151
Q

transition mutations

A

purine to purine or pyrimidine to pyrimidiyne

152
Q

transverion muations

A

purine to pyrimidine

153
Q

what is a major cause of aneuploidy?

A

nondisjunction

154
Q

aneuploidy

A

an abnormality in the number of chromosomes in a cell due to loss or duplication. an example is down syndrome

155
Q

what is an example of not a transition mutation

A

A to c

156
Q

what ploidy level does 3n=36 represent?

A

triploid

157
Q

human males introduce more point mutations (base substitutions) than females into the human gene pool. Is this true or false

A

true

158
Q

humans have how many pairs of chromosomes

A

23 pairs

159
Q

synthesis dependent strand anneling

A

this mechanism is initiated if DNA has already been synthesized. it is an error free repair mechanism

160
Q

Chromosomal aberrations occur at a lower frequency than spontaneous mutations in humans. this statement is true or false?

A

false

161
Q

down syndrome is caused by

A

an insertion

162
Q

what is a close approximation of spontaneous mutation rate in humans?

A

10x10^-9

163
Q

which agent of population genetics refers to chance fluctations of allele frequences resulting from sampling error and is more prominent in small, isolated populations?

A

gene drift

164
Q

which of the following best predicts the response of a trait to artificial selection?

A

h^2

165
Q

A region of a chromosome NOT spanning the centromere is broken and reattached in the reverse direction. This is an example of which type of chromosomal defect?

A

paracentric inversion

genetics (4 decks)

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