Exam IV Practice Exam Flashcards
(25 cards)
Unlike most examples of this trait, the height characteristic that Mendel studied in pea plants exhibited _____ variation.
A. continuous
B. discontinuous
C. meristic
D. threshold
E. quantitative
B. discontinuous
___ can cause a single genotype to produce a range of potential phenotypes
A. Epistasis
B. Genetic variance
C. Threshold effects
D. Environmental effects
E. Heritability
D. Environmental effects
A series of experiments shows that oil content in a diploid grain is influenced by five genes (a through e) with additive alleles. The highest-producing strain has 20% oil content; the lowest has close to 0%. A plant of unknown genotype has an oil content of 12%. What is a possible genotype for this plant (+ = additive alleles)?
A. a+ a+ b+ b+ c+ c+ d+ d e+ e
B. a+ a+ b+ b+ c c d d e e
C. a+ a+ b+ b c c d d e e
D. a a b+ b c+ c d+ d+ e+ e+
E. a+ a+ b+ b+ c+ c+ d+ d e e
D. a a b+ b c+ c d+ d+ e+ e+
There are five genes - but ten alleles.
By additive , means they all have the same amount of contribution to the phenotype.
Therefore, at 0% = 0+alleles, and at 20% = 20+alleles
Therefore, for each plus superscript you add, you add 2% because 20%/10 alleles = 2%.
So for 12%, only D has 6 alleles with a plus superscript and therefore, has an oil content of 12%.
(side note: in this problem, 0% would be no wild type (or additive alleles), and 20% would be all wild type (or additive alleles))
The _____ is the statistic that measures the spread of a distribution around the mean.
A. mean
B. correlation coefficient
C. regression coefficient
D. variance
D. variance
Heritability indicates the:
A. degree to which a characteristic is genetically determined.
B. proportion of phenotypic variation in a trait that is due to genetic differences.
C. degree to which a characteristic is environmentally determined.
D. proportion of phenotypic variation in a trait that is due to the environment.
E. extent to which identical twins are phenotypically similar.
B. proportion of phenotypic variation in a trait that is due to genetic differences.
The estimated broad-sense heritability for milk production in a herd of dairy cattle is high. Which of the following statements is a valid inference?
A. Most of the variation in milk production in the herd is due to additive genetic variance within the herd.
B. Most of the variation in milk production in the herd is due to dominant genetic variance.
C. Little of the variation in milk production is due to environmental variation within the herd.
D. Selective breeding for high milk production in this herd will be effective.
E. Broad-sense heritability for milk production will be high in most other herds of dairy cattle.
C. Little of the variation in milk production is due to environmental variation within the herd.
Phenotypic variation in tail length of unicorns has the following components:
Additive genetic variance = 0.2
Dominance genetic variance = 0.5
Environmental variance = 0.2
Genetic–environmental interaction variance = 0.5
What is the broad-sense heritability for tail length in these unicorns?
A. 0.14
B. 0.3
C. 0.5
D. 0.7
E. 1.4
C. 0.5
Phenotypic variation in tail length of unicorns has the following components:
Additive genetic variance = 0.2
Dominance genetic variance = 0.5
Environmental variance = 0.2
Genetic–environmental interaction variance = 0.5
What is the narrow-sense heritability for tail length in these unicorns?
A. 0.14
B. 0.3
C. 0.5
D. 0.7
E. 1.4
A. 0.14
The ___ is all the genetic information within a Mendelian population
A. effective population size
B. Hardy-Weinberg equilibrium
C. fitness
D. genotypic frequency
E. gene pool
E. gene pool
A new kind of tulip is produced that develops only purple or pink flowers. Assume that flower color is controlled by a single-gene locus and that the purple allele (C) is dominant to the pink allele (c). A random sample of 1000 tulips from a large cultivated field yields 847 purple flowers and 153 pink flowers. What is the frequency of the purple and pink alleles in this field population?
A. purple allele frequency = 0.847, pink allele frequency = 0.153
B. purple allele frequency = 0.153, pink allele frequency = 0.847
C. purple allele frequency = 0.82, pink allele frequency = 0.18
D. purple allele frequency = 0.61, pink allele frequency = 0.39
E. purple allele frequency = 0.39, pink allele frequency = 0.61
D. purple allele frequency = 0.61, pink allele frequency = 0.39
p + q = 1 –> for alleles
p^2 + 2pq + q^2 = 1 –> for genotypes
We need the GENOTYPE frequency equation for the first part of the calculation:
Because pink is recessive, we know q^2 = 0.153, but for the dominant allele which is purple, [p^2 + 2pq] = 0.847
q^2 = 0.153 –> q = 0.391
So now we see what p equals, so NOW plug it into the ALLELE frequency equation, p + q = 1 and we get 1-0.391 = 0.609.
(If we had to calculate heterozygotes, plug it into 2pq = 1(0.609)(0.391) = 0.476, 0.476*1000 = 476 individuals –> are there actually 476 indivdiuals?
–> NO, b/c this is an expectency/prediction.
Which of the following does NOT bring about evolution in a population?
A. small population size
B. migration of individuals from a population with a different genetic structure
C. mutation
D. selection
E. random mating
E. random mating
One way to define ____ is any change in allelic frequencies within a population.
A. mutation
B. natural selection
C. equilibrium
D. evolution
E. sampling error
D. evolution
The ___ measures the probability of alleles being identical by descent.
A. selection coefficient
B. inbreeding coefficient
C. gene pool
D. Hardy–Weinberg law
E. migration rate
B. inbreeding coefficient
_____ is the product of sampling errors and chance events that may result in changes in allelic frequencies.
A. Mutation
B. Genetic drift
C. Natural selection
D. Inbreeding
E. Evolution
B. Genetic drift
_____ is the movement of genes between populations
A. Evolution
B. migration
C. outcrossing
D. genetic drift
B. migration
Which agent of evolution tends to reduce genetic variation between populations and increase genetic variation within each population?
A. natural selection
B. mutation
C. migration
D. genetic drift
C. migration
The process by which ancient hominids and chimpanzees split from a common ancestor is called:
A. Genesis
B. Anagenesis
C. Cladogenesis
D. Phylogenesis
C. Cladogenesis
The biological species concept distinguishes species based on:
A. genetic differences.
B. phenotypic differences.
C. time since anagenesis.
D. reproductive isolating mechanisms.
D. reproductive isolating mechanisms.
Based on the gene tree in the image, which of the following pairs of genes are MOST similar?
(Image In My Genetics Folder)
A. tilapia PRL1 and cherry salmon SOMA
B. human SOMA and human PRl
C. alligator PRL2 and chicken PRL
D. catfish PRL and chicken SOMA
E. whale PRL and catfish PRL
C. alligator PRL2 and chicken PRL
Based on the figure from previous question 19 (Check Genetics Folder For Iamge): which pair of genes was the EARLIEST to diverge?
A. sea bass PRL and tilapia PRL2
B. sea bass PRL and eel PRL
C. sea bass PRL and tilapia PRL1
D. eel PRL and catfish PRL
E. catfish PRL and carp PRL
B. sea bass PRL and eel PRL
The _____ approach to inferring relationships among species selects the phylogeny that minimizes the number of evolutionary changes.
A. maximum likelihood
B. Bayesian
C. parsimony
D. rooted tree
E. distance-based
C. parsimony
What proportion of human variation is explained by within-population variance?
A. 0.6%
B. 4%
C. 15%
D. 96%
D. 96%
Which of the following were NOT a consequence of the American Eugenics movement?
A. Forced sterilization
B. Bans on Inter-racial marriage
C. SAT tests
D. Darwin’s The Origin of Species
E. Immigration reform
D. Darwin’s The Origin of Species
Why does sickle-cell Anemia persist in certain populations?
A. Genetic drift in African populations
B. Heterozygotes for sickle-cell have the highest fitness when malaria is present.
C. Malaria exerts selection favoring homozygous sickle-cell blood.
D. Blood oxygen levels are not as important in the warm areas of sub-saharan Africa, malaria is more important.
B. Heterozygotes for sickle-cell have the highest fitness when malaria is present.
