Test 2

Question 1

In humans, how might you determine whether a particular trait is due to cytoplasmic inheritance?

A. Will always be passed through females
B. Will always be passed through males
C. Can only be determined upon sequencing of the mitochondrial DNA of both the offspring and the parents
D. Can be visually distinguished under the microscope based upon morphologic analysis of the organelles
E. None of the above

Answer 1

A. Will always be passed through females

Question 2

While inheritance is one vital part of genetic risk, factors that alter how genes behave, can have effects just as damaging as inheriting a gene that increases risk of disease. These factors, collectively referred to as ‘epigenic’ control when inherited genes are expressed or turned on. Choose the statement below that is false in the context of epigenetic control.

A. As tissues begin to develop in the embryo, while that all contain the same genes, epigenic factors control which genes are turned on or off in which tissues - a process called fetal programming.
B. many health conditions are affected by fetal programming, including heart disease, diabetes, obesity and cancers.
C. Individuals with identical genes can exhibit variable phenotypes due to differences in epigenic modifications
D. Environmental factors can alter epigenic control of gene expression.
E. All of the above

Answer 2

E. All of the above

Question 3

Genomic imprinting has been implicated in several human disorders, including Prader-Willi syndrome. In the context of Prader- Willi Syndrome, the affected individual is missing a small region on the long arm of chromosome 15. Choose the statement below that is true in the context of this disorder and phenomenon of genomic imprinting.
A. This deletion is always inherited from the father and, as a result, the affected individuals lack a parental copy of the gene
B. An affected individual inherited a deletion of the gene from the father and a mutated gene from the mother
C. The child inherited a ‘good’ copy of the gene from the mother that is silenced due to genomic imprinting
D. All of the above are true
E. Only answers A and C are true

Answer 3

E. Only answers A and C are true

Question 4

The agouti locus helps determine coat color in mice. Parents that have identical DNA sequences but have different degrees of methylation on their DNA may give rise to offspring with different coat colors. Such epigenic changes have been observed in a number of organisms and are responsible for a variety of phenotypic effects. Which of the following statements below is false in the context of epigenic changes?
A. Alterations to DNA that do not include a change in the base sequence
B. the result of a mutation to the DNA sequence
C. Often influenced by environmental factors
D. They are capable of being reversed
E. All of the above

Answer 4

B. the result of a mutation to the DNA sequence

Question 5

Which of the following are true regarding the inheritance of X-linked recessive traits in humans?
A. Homozygous females are mosaics for these traits
B. Because males are hemizygous, these traits are expressed in every generation
C. Affected males pass these alleles on to all of their daughters
D. Females are affected by these traits more frequently than males
E. None of the above

Answer 5

C. Affected males pass these alleles on to all of their daughters

Question 6

A y-linked trait will affect only males, appear in every generation (as long as there are sons) and is always passed from father to son.
True or False

Answer 6

true

Question 7

An inherited disease that affects women and not men is likely to be caused by:
A. A mutation in a gene on a non-sex chromosome or autosome
B. A mutation in a gene on the X chromosome
C. A mutation in a gene on the Y chromosome
D. Without additional information either A or B is possible

Answer 7

D. Without additional information either A or B is possible

Question 8

Concordance values for epilepsy among monozygotic and dizygotic twins from early development study revealed that following data:
Monozygotic - 1237 pairs of twins - 73% concordance
Dizygotic - 2426 pairs of twins - 23% concordance
What can you conclude from the data? Choose the statement that best answers the question.
A. Epilepsy is strongly influenced by genetic factors
B. Epilepsy is only influenced by genetic factors
C. Epilepsy is strongly influenced by environmental factors
D. Epilepsy is only influenced by environmental factors
E. Epilepsy is strongly influenced by genetic factors but environmental factors are also influential

Answer 8

E. Epilepsy is strongly influenced by genetic factors but environmental factors are also influential

Question 9

The allele that causes yellow coat color in mice is embryonic lethal in utero in mice homozygous from the gene. In addition to its lethality and effect on coat color, the gene has been found to cause a diabetes like condition, obesity, and an incresed propensity to develop tumors. What genetic term can be applied to this gene?
A. Polygeny
B.Pleiotrophy
C. epistasis
D. Genetic conflict
E. Environmental effect

Answer 9

B.Pleiotrophy

Question 10

In a testcross for two genes, the following types of gametes could be produced:
A. nonrecombinant
B. 50% recombinant gametes and 50% nonrecombinant gametes
C. More than 50% of the gametes nonrecombinant and less than 50% recombinant gametes

Which of the above gametes would represent genes that are incompletely linked?

Answer 10

C. More than 50% of the gametes nonrecombinant and less than 50% recombinant gametes

Question 11

In the context of performing genetic tests to determine complete linkage compared to independant assortment, which of the following statements below is not true of a testcross.
A. A testcross reveals the effects of linkage
B. A testcross typically includes one parent that is heterzygous and one parent that is homozygous recessive for all gene loci being examined.
C. A testcross typically includes one parent that is homozygous dominant and one parent that is homozygous recessive for all the loci being examined
D. the traits that appear in the progeny reveal which alleles were transmitted by the heterozygous parent
E. All of the above

Answer 11

C. A testcross typically includes one parent that is homozygous dominant and one parent that is homozygous recessive for all the loci being examined

Question 12

Choose the statement below that is not true of linked genes. Linked genes - ?
A. Are located close together on the same chromosome
B. Assort randomly
C. Are in the same linkage group
D. Travel together during meiosis
E. Are not allelic

Answer 12

B. Assort randomly

Question 13

mutations that change the structures of individual chromosomes

Answer 13

chromosome rearrangements

Question 14

one or more complete sets of chromosomes are added

Answer 14

polyploidy

Question 15

when a single copy of a gene is not adequate to produce a wild-type phenotype

Answer 15

haploinsufficiency

Question 16

the expression of a normally recessive mutation

Answer 16

pseudodominance

Question 17

Chromosomes duplications typically result in abnormal phenotypes because developmental processes are affected by increased amounts of gene products.
A. True
B. False
C. Unknown

Answer 17

A. True

Question 18

The following testcross (Aa Bb x aa bb) produces the progeny: 10 Aa Bb, 40 Aa bb, 40 aa Bb, 10 aa bb.

Q; Where the genes in coupling or repulsion

Answer 18

B. Repulsion

Question 19

A diploid organism has 2n= 32 chromosomes. How many chormosomes would be found in a trisomic member of species?

A. 16
B. 33
C. 64
D. 65
E. 96

Answer 19

B. 33

Question 20

Which of the following notations represents a triploidy?

A. 2n-1
B. 2n
C. 2n+1
D. 3n 
E. none of the choices

Answer 20

D. 3n

Question 21

Translocations can affect a phenotype in several ways. Which of the following is false in the context of the effects of translocations.

A. Genes translocated to new locations often behave normally
B. Genes translocated to new locations may come under control of different regulatory sequences or other genes that affect their expression.
C. The chromosomal breaks that occured during the process of the translocation event may have broken a gene and resulted in a disruption of its function
D. They can physically link genes that were formerly located on different chromosomes
E. None of the above

Answer 21

A. Genes translocated to new locations often behave normally

Question 22

Which of the following represents a nonreciprocal translocation between chromosomes ABCDEFG and MNOPQRS?

A. ABCDQURG AND MNOPQRS
B. ABCDG AND MNOPQFG
C. ABCDG AND MNOPEFQRS
D. MNCDEFG AND ABOPQRS

Answer 22

C. ABCDG AND MNOPEFQRS

Question 23

In rare cases, some children that express recessive genetic diseases have only one parent that is heterozygous for the disease allele. If the parents are the true biological parents of the affected child, what is a genetic explanation for this observation?

A. Robertsonian translocation
B. Uniparental disomy
C. Gene duplication
D. Unbalenced gene dosage
E. None of the above

Answer 23

B. Uniparental disomy

Question 24

Which term refers to mating between closely related people?

A. Consanguinity
B. Concordance
C. Congenital
D. Probaning

Answer 24

A. Consanguinity

Question 25

The Hardy-Weinberg law is a mathmatical model that evaluates the effect of reproduction on the genotypic and allelic frequencies of a population. It makes several simplifying assumptions about a population, what are they?

A. the population is large
B. The population is not affected by natural selection
C. The population is randomly mating
D. the population is not affected by migration or mutation
E. All of the above

Answer 25

E. All of the above

Question 26

Genetic variation is the basis of all evolution, and the extent of genetic variation within a population affects its potential to adapt to environmental change

A. True
B. False
C. Unknown

Answer 26

A. True

Question 27

What phenomenon describes a genetic trait that is expressed more strongly or at an earlier age with each generation?

A. genomic imprinting
B. epistasis
C. maternal effect
D. genetic anticipation
E. none of the above

Answer 27

D. genetic anticipation

Question 28

The Hardy-Weinberg law is a mathmatical model in which allele frequencies in populations remain constant from generation to generation. Given all the conditions that must be met for the Hardy-Weinberg equation to be valid, why is this equation useful for studying population genetics?

A. By specifying the ideal conditions that must be met for allele frequencies to remain constant in populations, the Hardy-Weinberg law can identify evolutionary forces that can cause changes in allele frequencies in the real world
B. The hardy- Weinberg law is amodel and thus, by definition, provides simplistic view of reality
C. The Hardy-Weinberg law serves as a staring point and basis for comparison for further examination and description of real populations
D. All of the above
E. none of the above

Answer 28

D. All of the above

Question 29

A population can be in Hardy-Weinberg equilibrium for one locus but not for others.

A. True
B. False
C. Unknown

Answer 29

A. True

Question 30

Rapid changes in allelic frequencies by ____ take place in populations that are small.

A. Inbreeding
B. mutation
C. genetic drift
D. outcrossing
E. natural selection

Answer 30

C. genetic drift

Question 31

If there is random mating in a population and no evolutionary forces are acting on the population, what will be the expected outcome?

A. The allele frequencies will remain the same, but the genotype distribution will change

B. The genotype distribution will remain the same, but the allele frequencies will change
D. Both the genotype distribution and the allele frequencies will remain the same
E. No prediction can be made about the genotype distribution and allele frequencies from one generation to the next

Answer 31

D. Both the genotype distribution and the allele frequencies will remain the same

Question 32

What is the expected frequency of heterozygotes in a population with allelic frequencies x and y that is in Hardy- Weinberg equilubrium?

A. x + y
B. xy
C. 2xy
D. (x+y)2
E. Unknown

Answer 32

C. 2xy

Question 33

A population of elf is isolated such that no new elk can come into their territory. Which of the following is primarily responsibe for the appearance of new alleles in this population?

A. Reassotment of chromosomes during the process of gametogenesis
B. muations in the cells that will become sperm or eggs (ie gametes)
C. Changes in the environment favor some elk traits over others
D. Random mating between elk in population
E. None of the above

Answer 33

B. muations in the cells that will become sperm or eggs (ie gametes)

Question 34

An isolated population of prairie dogs has longer than average teeth. As a result they can eat grass with less effort and are better able to survive. The mutations that resulted in longer teeth:

A. Allowed the teeth to grow longer over several generations until they reached an optimal length for grass eating
B. arose in many members of the population at the same time
C. Happened by chance
D. occurred because prairie dogs needed to be more efficient at eating grass and would not occur in a population that lives on seeds

Answer 34

C. Happened by chance

Question 35

Polydactyly is an inherited trait that results in extra fingers or toes. In the United States 0.1% of the population exhibits polydactyly and p represents the normal allele of this gene. Which of the following is true?

A. The P allele is more frequent in the US than the p allele
B. The P allele is less frequent in the US than the p allele
C. the 2 alleles, P and p, are at approximately equal frequencies in the population
D. There is not enough information to answer the question

Answer 35

B. The P allele is less frequent in the US than the p allele