Genetics final exam

The distribution of continuous traits can best be described as __________. See Section 21.2 (Page) . bell-shaped hyperbolic linear logarithmic

bell-shaped

What kind of heritability estimates (broad sense or narrow sense) are obtained from human twin studies? broad-sense narrow sense

broad-sense

If a recessive disease is found in 50 out of 100,000 individuals, what is the frequency of the heterozygote carriers for this disease? 0.022 0.043 0.0005 0.956

.043

In a population of 100 individuals, 49 percent are of the NN blood type. What percentage is expected to be MN assuming Hardy-Weinberg equilibrium conditions? 9 percent 21 percent 51 percent 42 percent There is insufficient information to answer this question.

42

Albinism is an autosomal recessive trait in humans. Assume that there are 100 albinos (aa) in a population of 1 million. How many individuals would be expected to be homozygous normal (AA) under equilibrium conditions? 980,100 10,000 19,800 999,900 100

980,100

What is the difference between an eQTL and a pQTL? See Section 21.5 (Page) . An eQTL is a proportion of an F2 population carrying the dominant phenotype, and a pQTL is the proportion containing the recessive phenotype. An eQTL phenotype is the amount of protein produced; a pQTL phenotype is the amount of RNA produced. The term eQTL refers to twins that both express a given trait; the term pQTL refers to twins where only one twin expresses the trait. A pQTL phenotype is the amount of protein produced; an eQTL phenotype is the amount of RNA produced.

A pQTL phenotype is the amount of protein produced; an eQTL phenotype is the amount of RNA produced.

__________ is a statistic used to measure the strength of an association between two traits. Covariance Standard deviation Mean Correlation coefficient

Correlation coefficient

All EXCEPT which of the following statements are major points in the multiple-gene hypothesis? Analysis of multiple-gene traits requires the study of large numbers of progeny. Together, the genes controlling the trait under study produce a wide range of phenotypic variations. Each gene locus involved in the phenotype may be occupied by either an additive allele, which contributes to the phenotype, or a nonadditive allele, which offsets the additive alleles. Each additive allele contributes roughly equally to the phenotype

Each gene locus involved in the phenotype may be occupied by either an additive allele, which contributes to the phenotype, or a nonadditive allele, which offsets the additive alleles.

What findings led geneticists to postulate the multiple-factor hypothesis that invoked the idea of additive alleles to explain inheritance patterns? What findings led geneticists to postulate the multiple-factor hypothesis that invoked the idea of additive alleles to explain inheritance patterns? Experimental results involving Drosophila eye color mutations showed that a number of additive alleles acting in Mendelian fashion could explain continuous variation. Incomplete dominance shown in the experiment of crossing red and white colored snapdragon plants could explain continuous variation. Mendel's experiment results involving flower pigmentation of pea plants showed that a number of additive alleles could explain continuous variation. Experimental results involving pigmentation in wheat showed that a number of additive alleles acting in Mendelian fashion could explain continuous variation.

Experimental results involving pigmentation in wheat showed that a number of additive alleles acting in Mendelian fashion could explain continuous variation.

Which of the following statements about twins and twin studies is FALSE? Fraternal twins are as close genetically to each other as are monozygotic twins. Dizygotic twins are an important control for any study using monozygotic twins. Twin studies have been used to try to determine the role of heredity versus environment. If the concordance values for monozygotic twins are much higher than for dizygotic twins, the trait probably has a strong genetic basis.

Fraternal twins are as close genetically to each other as are monozygotic twins.

A number of mechanisms operate to maintain genetic diversity in a population. Why is such diversity favored? Greater genetic diversity increases the chances of haploidy. Genetic diversity helps populations avoid diploidy. Diversity leads to inbreeding advantages. Homozygosity is an evolutionary advantage. Genetic diversity may better adapt a population to inevitable changes in the environment.

Genetic diversity may better adapt a population to inevitable changes in the environment.

Which of the following statements best describes the relationship between the Hardy-Weinberg principle and the effects of natural selection? The Hardy-Weinberg equation assumes that all genotypes occur with equal frequency, but if there is selection against one or more genotypes, equal frequency of all genotypes is not possible. If it can be determined that selection favors a particular genotype, the Hardy-Weinberg equation should not be applied. If selection can be quantified, relative fitness values can be calculated and used to appropriately modify the Hardy-Weinberg equation. Natural selection can influence the genotype frequencies predicted by Hardy-Weinberg, but allele frequencies are not affected.

If selection can be quantified, relative fitness values can be calculated and used to appropriately modify the Hardy-Weinberg equation.

Which of the following statements about inbreeding in a natural population is true? See Section 22.8 (Page) . It is likely to occur as population size increases. It occurs when mating individuals are less closely related than any two individuals drawn from the population at random. It can increase the frequency of homozygotes. It increases the genetic variation in a population.

It can increase the frequency of homozygotes

What is the difference between multiple alleles and additive alleles? Additive alleles are different forms of the same gene. Multiple alleles are alleles of different genes affecting different traits. Multiple alleles are different forms of the same gene. Additive alleles are alleles of different genes, all of which affect the same trait. Additive alleles is another term for multiple alleles. Multiple alleles are alleles of different genes affecting the same trait. Additive alleles are different forms of the same gene.

Multiple alleles are different forms of the same gene. Additive alleles are alleles of different genes, all of which affect the same trait.

Which of the following statements about mutations in population genetics is true? See Section 22.5 (Page) . Except in situations of Hardy-Weinberg equilibrium, mutation plays a significant role in changing allelic frequencies. Mutation is a major force in generating genetic variability, but by itself plays a relatively insignificant role in changing allelic frequencies. The mutation rate is equal to the allelic frequency of the recessive allele divided by the initial frequency of the recessive allele. Mutation frequencies can be calculated from the frequency of the homozygous recessive genotypic class alone

Mutation is a major force in generating genetic variability, but by itself plays a relatively insignificant role in changing allelic frequencies.

If an individual with the minimum height specified by these genes marries an individual of intermediate or moderate height, will any of their children be taller than the tall parent? Why or why not? Yes, if the individual of moderate height is RrSsTtUu. Yes, if the individual of moderate height is rrSsTtUu. Yes, if the individual of moderate height is RRSSttuu. No, there is no way of having more than four uppercase alleles in the offspring.

No, there is no way of having more than four uppercase alleles in the offspring

Regarding efficiency of reproductive isolation mechanisms, which one of the following statements is true? Prezygotic mechanisms are most efficient because they occur before resources are expanded in the processes of mating. Prezygotic mechanisms are most efficient because of hybrid nonviability. Postzygotic mechanisms are most efficient because of seasonal differences when the populations are sexually mature. Postzygotic mechanisms are most efficient because of hybrid nonviability.

Prezygotic mechanisms are most efficient because they occur before resources are expanded in the processes of mating.

If the farmer selects for cows producing more butterfat in their milk, what will be the most likely effect on milk protein content in the next generation? Protein content will increase. Protein content will not change. Protein content will decrease. It is impossible to predict protein content change from the data given.

Protein content will increase.

**new What is the difference between broad-sense heritability and narrow-sense heritability?

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Which of the following statements does NOT fit the Wallace-Darwin theory of evolution? See Section 22.4 (Page) . The number of individuals in a population will always be maintained at a level to minimize competition. Some individuals will be more successful at survival than others and be more likely to reproduce. Individuals within a species will have minor variations in phenotypes. Given enough time, heritable variations in phenotype can lead to new species.

The number of individuals in a population will always be maintained at a level to minimize competition.

The percentage of heterozygous carriers can be calculated by the expression p=2×(p0.5)×(1−p0.5)×100. What must be assumed in order to use the expression? The population must be very large. The population must very small. The population must be in Hardy-Weinberg equilibrium. The population must be isolated..

The population must be in Hardy-Weinberg equilibrium.

Which of the following statements best describes the relationship between fitness and selection coefficient (s)? The stronger the selection against a given genotype, the lower the fitness associated with that genotype. Fitness is a qualitative measure whereas selection is a quantitative measure. The lower the fitness value associated with a given genotype, the weaker the selection against that genotype. The higher the fitness value associated with a given genotype, the stronger the selection against that genotype.

The stronger the selection against a given genotype, the lower the fitness associated with that genotype.

Why would you suspect neutral sequences to be located in noncoding genomic regions? They don't contribute to phenotype (or contribute little), therefore they are selectively neutral. They contribute to phenotype, therefore they are not selectively neutral. They contribute to phenotype, therefore they are selectively neutral. They don't contribute to phenotype (or contribute little), therefore they are not selectively neutral

They don't contribute to phenotype (or contribute little), therefore they are selectively neutral.

Which of the following statements describes the members of a population? . They must have the same allele for at least one genetic locus. They all have the same genotype. They can include all of the plants and animals within a geographic area. They must be able to interbreed with one another.

They must be able to interbreed with one another.

Polygenes are involved in determining continuously varying or multiple-factor traits. True False

True

The multiple factor hypothesis suggests that many factors or genes contribute to the phenotype in a cumulative or quantitative manner. True False

True

Can two individuals of moderate height produce offspring that are much taller or shorter than either parent? If so, how? Yes, the example of the crossing is: rrSsTtuu × RrSsTtUu Yes, the example of the crossing is: RRSSTTUU × RrSsTtUu Yes, the example of the crossing is: RRSSttuu × rrssTTUU No.

Yes, the example of the crossing is: rrSsTtuu × RrSsTtUu

Which of the these factors are important in generating populations with substantial genetic differences? geographic isolation migration genetic drift mutation all of the above

all of the above

Which term describes the procedure of selecting a specific group of organisms from an initially heterogeneous population for future breeding purposes? . broad-sense heritability artificial selection selection differential narrow-sense heritability

artificial selection

Which term is defined as "a measure of the variation in a phenotype (for a polygenic trait in a given population) due to genetic factors"? See Section 21.3 broad-sense heritability response narrow-sense heritability variance

broad-sense heritability

How do we assess environmental factors to determine if they impact the phenotype of a quantitatively inherited trait? by correlating the number of environmental factors with types of heritability by estimating the number of polygenes by estimating the number of offspring produced by heritability estimation

by heritability estimation

Quantitative inheritance involves the interaction of a number of gene loci. The pattern of genetic transmission typical of quantitative inheritance is ________. a 9:3:3:1 ratio continuous variation of phenotypic expression typical of Mendelian inheritance usually a pattern that clearly reflects dominance and recessiveness discontinuous distributions such as 3:1

continuous variation of phenotypic expression

Molecular clocks are used to __________. . track the amount of time for a species to become extinct determine evolutionary relatedness by assessing the molecular relatedness of different organisms date various fossils alter the rates of mutation in different species

determine evolutionary relatedness by assessing the molecular relatedness of different organisms

How do we know that monozygotic twins are not identical genotypically as adults? differences in height differences in inherited disease states differences in social behavior differences in gestures and speech

differences in inherited disease states

Which method is often used to analyze proteins and nucleic acids by physical separation when estimating genetic variation in populations? centrifugation electrophoresis absorption spectrophotometry fluorometry in situ hybridization

electrophoresis

Which term is given to the total genetic information carried by all members of a population? gene pool chromosome complement breeding unit genome race

gene pool

Founder effect and genetic bottlenecks give rise to __________. See Section 22.7 (Page) . migration inbreeding natural selection genetic drift

genetic drift

In small isolated populations, gene frequencies can fluctuate considerably. The term that applies to this circumstance is ________. genetic drift stabilizing selection natural selection allelic separation genetic isolation

genetic drift

Of the human traits listed below, which are likely to be under the control of a polygenic mode of inheritance? sickle cell anemia height skin color ABO blood type intelligence color blindness

height skin color intelligence

new** Which of the following circumstances might allow a lethal dominant allele to persist in a population? select all that apply late onset (lethality occurs after reproductive age) natural selection against the allele nonrandom mating incomplete penetrance

late onset and incomplete penetrance

Phenotypes that exhibit continuous variation are often the result of __________. See Chapter 21 (Page) . . multiple alleles epistasis multifactorial inheritance the effect of a single gene

multifactorial inheritance

Assume that a cross is made between tall and dwarf tobacco plants. The F1 generation showed intermediate height, whereas the F2 generation showed a distribution of height ranging from tall to dwarf, like the original parents, and many heights between the extremes. These data are consistent with which one of the following modes of inheritance? incomplete dominance alternation of generations hemizygosity multiple-factor inheritance codominance

multiple-factor inheritance

Bell-shaped distributions produced by plotting results of F2 and F3 crosses are typical of which type of inheritance? alternation of generations codominance multiple-factor inheritance incomplete dominance hemizygosity

multiple-factor inheritance

Allele frequencies within a population can be altered by all EXCEPT which of these processes? natural selection nonrandom mating migration mutation

nonrandom mating

What genetic changes take place during speciation? Select the two correct answers. destruction loss of heterozygosity duplication point mutations chromosomal changes

point mutations chromosomal changes

Environmental factors typically influence inheritance of codominance multiple alleles dominantly inherited traits trihybrid crosses polygenic traits

polygenic traits

________ is a group of individuals belonging to the same species that live in a defined geographic area and actually or potentially interbreed. Cohort Hybrid Pool Pod Population

population

What are the two groups of reproductive isolating mechanisms? Select the two that apply. prezygotic postzygotic speciation post-speciation

prezygotic and postzygotic

Characteristics exhibited by continuously varying traits include ________. sex-linked genes only a 9:3:3:1 ratio autosomal genes only 3:1 and 1:1 ratios quantification by measuring, weighing, counting, etc.

quantification by measuring, weighing, counting, etc.

Which general term is used to group various biological and behavioral properties of organisms that act to prevent or reduce interbreeding? phyletic evolution reproductive isolating mechanisms allopatric speciation genetic divergence inbreeding

reproductive isolating mechanisms

Which term describes the degree to which values diverge from the mean? See Section 21.2 (Page) . central tendency sample variance average standard error of the mean

sample variance

All of the alleles of the members of a population are known as __________. genetic drift the gene pool speciation phylogeny

the gene pool

The theoretical population described by the Hardy-Weinberg model is based on all the following assumptions EXCEPT __________. . individuals of all genotypes have equal rates of survival and equal reproductive success individuals do not migrate into or out of the population the population size is small individuals in the population mate randomly

the population is small

Fitness is a measure of __________. See Section 22.4 (Page) . the longevity of organisms with a particular genotype an organism's increased ability to survive an organism's physiological vigor the reproductive output of organisms relative to the alternative genotypes

the reproductive output of organisms relative to the alternative genotypes

How many gene pairs are involved in the inheritance of size in these strains of guinea pigs? four two three five

three