Quiz 12 Q's Flashcards
In a human population, the genotype frequencies at one locus are 0.5 AA, 0.4 Aa, and 0.1 aa. The frequency of the A allele is
0.70
Human albinism is an autosomal recessive trait. Suppose that you find a village in the Andes where one-fourth of the population is albino. If the population size is 1000 and the population is in Hardy–Weinberg equilibrium with respect to this trait, how many individuals are expected to be heterozygotes?
500
You are studying an X-linked trait. There are two alleles, one showing complete dominance over the other. In females, 84% show the dominant phenotype. What percentage of the males will show the dominant phenotype, assuming that individuals in this large population mate at random with respect to this trait?
60%
In a tropical human population in Hardy–Weinberg equilibrium for an autosomal locus determining presence/absence of pigment in the skin, the frequency of albinism (aa) is 1 in 10,000. The frequency of heterozygotes is approximately
1 in 50
If the frequency of the recessive allele that causes phenylketonuria (PKU) when homozygote is about 0.01 in European and American populations, what is the estimated heterozygote frequency in these populations? (Assume that people mate randomly with respect to PKU, and that the mutant allele does not have any effects on fitness.)
about 0.0198
A high variance indicates that
the variation among the values is high.
most values are higher than the mean.
most values are lower than the mean.
the mean value is very high.
most values are very close to the mean.
the variation among the values is high
Which of the following statements is/are a central assumption of the multifactorial inheritance hypothesis?
Only one locus is associated with the trait.
None of the answer options is correct.
Only one locus is associated with the trait, and environment interacts with this locus to produce the final phenotype.
Environment plays no role in the final phenotype.
Several loci are associated with the trait.
several loci are associated with the trait
The amount of milk produced per day by a cow is an example of a
discrete trait.
meristic trait.
threshold trait.
dominant trait.
continuous trait.
continuous trait
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
differences in the plants’ microenvironment.
the use of a nonrepresentative sample to compute the mean.
a correlation between genotype and environment.
random genetic differences within the population.
the difference between the greenhouse population mean and the whole population mean.
differences in the plants’ microenvironment
When all of the variation in a population is due to environmental sources and there is no genetic variation, broad-sense heritability (H2) is
zero and all of the phenotypic variability is due to environment.
some negative value indicating the phenotypic variability is due to some recessive loci.
zero and all of the phenotypic variability is due to loci at other locations.
some positive value indicating the phenotypic variability is due to some dominant loci.
zero and all of the phenotypic variability is due to environment
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
in the population tested, 75% of the variance in bill length is due to genetic differences among individuals.
The variance in tail length in a large population of genetically diverse mice is found to be 21.30. The broad-sense heritability for this trait in an identical population was found to be 0.8. Based on this information, what is the predicted genetic variance (Vg) for these mice?
17.04
It is difficult to measure any type of heritability without the ability to perform specific crosses. However, vast population studies enable estimation of heritability for some characters in human beings. Some estimated broad-sense heritabilities include the following:
Character
H2
stature
0.85
body weight
0.62
systolic blood pressure
0.57
diastolic blood pressure
0.44
twinning
0.50
Which of these characteristics is most likely to “run in families”?
stature
Narrow-sense heritability (h2) is a quantification of the proportion of total variance due to
additive genetic variance
If 64% of the people in a population are blue-eyed and the population is in Hardy–Weinberg equilibrium, what is the percentage of heterozygotes in the population?
32%
