Question 1

What would be the results of a test cross with the F1 flies?

Accepted Answer

A) 1 brown eye, thin wing veins: 1 red eye, heavy wing veins 
B) 1 brown eye, heavy wing veins: 1 red eye, thin wing veins 
C) 1 brown eye, thin wing veins: 2 red eye, thin wing veins: 1 red eye, heavy wing veins 
D) 1 brown eye, heavy wing veins: 2 red eye, thin wing veins: 1 red eye, thin wing veins 
A) 1 brown eye, thin wing veins: 1 red eye, heavy wing veins 
B) 1 brown eye, heavy wing veins: 1 red eye, thin wing veins 
C) 1 brown eye, thin wing veins: 2 red eye, thin wing veins: 1 red eye, heavy wing veins 
D) 1 brown eye, heavy wing veins: 2 red eye, thin wing veins: 1 red eye, thin wing veins

Question 2

Given that these two gene loci are very closely linked, the genotypic ratio in the F2 generation should be closest to

Accepted Answer

A) 1:2:1 
B) 1:1:1:1 
C) 9:3:3:1 
D) 3:1 
A) 1:2:1 
B) 1:1:1:1 
C) 9:3:3:1 
D) 3:1

Question 3

Amniocentesis is a procedure that is normally used

Accepted Answer

A) to reduce the risk of genetic disease. 
B) for gene therapy. 
C) to change the sex of the fetus. 
D) for diagnosis of genetic disorders. 
A) to reduce the risk of genetic disease. 
B) for gene therapy. 
C) to change the sex of the fetus. 
D) for diagnosis of genetic disorders.

Question 4

Traits that are controlled by genes located on the X chromosome are said to be ________________.

Accepted Answer

A) autosomal 
B) gametal 
C) sex-linked 
D) pleiotropic 
A) autosomal 
B) gametal 
C) sex-linked 
D) pleiotropic

Question 5

In Drosophila, dosage compensation is controlled by the male-specific lethal (MSL) complex consisting of MSL proteins and roX RNAs.Based on what you know about dosage compensation, the role of the MSL complex in males would be to

Accepted Answer

A) double the level of expression of genes on the X chromosome. 
B) increase the level of expression of genes on the X chromosome by 50%. 
C) decrease the level of expression of genes on the X chromosome by 50%. 
D) decrease the level of expression of genes on the X chromosome by 100%. 
A) double the level of expression of genes on the X chromosome. 
B) increase the level of expression of genes on the X chromosome by 50%. 
C) decrease the level of expression of genes on the X chromosome by 50%. 
D) decrease the level of expression of genes on the X chromosome by 100%.

Question 6

In humans, if non-disjunction led to an individual with a genotype of XXY, that person would

Accepted Answer

A) be female because each cell has two X chromosomes. 
B) be male because each cell has one Y chromosome. 
C) display both male and female characteristics. 
D) not survive. 
A) be female because each cell has two X chromosomes. 
B) be male because each cell has one Y chromosome. 
C) display both male and female characteristics. 
D) not survive.

Question 7

A deletion of a particular stretch of chromosome 15 can cause either Prader-Willi syndrome or Angelman syndrome, depending on

Accepted Answer

A) the parental origin of the normal and deleted chromosome. 
B) whether or not the region is methylated properly. 
C) whether a translocation event has occurred. 
D) whether a nondisjunction event has occurred. 
A) the parental origin of the normal and deleted chromosome. 
B) whether or not the region is methylated properly. 
C) whether a translocation event has occurred. 
D) whether a nondisjunction event has occurred.

Question 8

How did the development of anonymous markers aid in the production of a human genetic map?

Accepted Answer

A) Anonymous markers are genetic markers that do not cause a detectable phenotype, but can be detected by molecular techniques.The markers correspond to specific and unique chromosomal regions, thereby allowing for the identification and ordering of particular segments of DNA.Such information was essential to the generation of a human genetic map. 
B) Anonymous markers are genetic markers that cause a detectable phenotype and can't be detected by molecular techniques.The markers correspond to specific and unique chromosomal regions, thereby allowing for the identification and ordering of particular segments of DNA.Such information was essential to the generation of a human genetic map. 
C) Anonymous markers are genetic markers that do not cause a detectable phenotype, but can be detected by molecular techniques.The markers correspond to specific and unique genetic regions, thereby allowing for the identification and ordering of particular segments of the chromosome.Such information was essential to the generation of a human genetic map. 
A) Anonymous markers are genetic markers that do not cause a detectable phenotype, but can be detected by molecular techniques.The markers correspond to specific and unique chromosomal regions, thereby allowing for the identification and ordering of particular segments of DNA.Such information was essential to the generation of a human genetic map. 
B) Anonymous markers are genetic markers that cause a detectable phenotype and can't be detected by molecular techniques.The markers correspond to specific and unique chromosomal regions, thereby allowing for the identification and ordering of particular segments of DNA.Such information was essential to the generation of a human genetic map. 
C) Anonymous markers are genetic markers that do not cause a detectable phenotype, but can be detected by molecular techniques.The markers correspond to specific and unique genetic regions, thereby allowing for the identification and ordering of particular segments of the chromosome.Such information was essential to the generation of a human genetic map.

Question 9

The classic experiments performed by Creighton and McClintock in Maize

Accepted Answer

A) provided the initial evidence for genetic recombination. 
B) provided evidence that genes located on the same chromosome do not assort independently. 
C) allowed for the establishment of the first genetic map. 
D) provided evidence for the physical exchange of genetic material between homologues. 
A) provided the initial evidence for genetic recombination. 
B) provided evidence that genes located on the same chromosome do not assort independently. 
C) allowed for the establishment of the first genetic map. 
D) provided evidence for the physical exchange of genetic material between homologues.

Question 10

Of the 23 pairs of human chromosomes, 22 pairs are homologous and are found in both males and females.These are called ________.

Accepted Answer

A) bivalents 
B) autosomes 
C) recombinant chromosomes 
D) somatic chromosomes 
A) bivalents 
B) autosomes 
C) recombinant chromosomes 
D) somatic chromosomes

Question 11

Huntington's disease is caused by a single dominant allele.It is a lethal disease, yet it persists in the human population.Which of the following statements best describes why?

Accepted Answer

A) Huntington's disease is sex-linked and every human has at least one X chromosome; thus, the chances are extremely high for this allele to be maintained in the human population. 
B) Huntington's disease can present symptoms so mild that they appear to lack dominant expression of the allele in some individuals; in those cases, the allele is passed on to the offspring. 
C) While lethal to a parent, Huntington's disease will not be lethal to the offspring since it can skip a generation. 
D) Huntington's disease presents symptoms in mid-life, after most people have already had offspring. 
A) Huntington's disease is sex-linked and every human has at least one X chromosome; thus, the chances are extremely high for this allele to be maintained in the human population. 
B) Huntington's disease can present symptoms so mild that they appear to lack dominant expression of the allele in some individuals; in those cases, the allele is passed on to the offspring. 
C) While lethal to a parent, Huntington's disease will not be lethal to the offspring since it can skip a generation. 
D) Huntington's disease presents symptoms in mid-life, after most people have already had offspring.

Question 12

Which offspring inherit all their mitochondrial DNA from their mother and none from their father?

Accepted Answer

A) daughters 
B) sons 
C) both sons and daughters 
D) neither sons nor daughters 
A) daughters 
B) sons 
C) both sons and daughters 
D) neither sons nor daughters

Question 13

Morgan's student Sturtevant demonstrated that the recombination frequencies between a series of linked genes is additive.Examine the following recombination data from Sturtevant, and determine the proper order of the genes on the Drosophila X chromosome.Assume y is in the 0.0 position.Gene 1 Gene 2 Recombination frequency yellow(y) vermilion(y) 0.322 vermilion miniature(m) 0.030 white(w) vermiliom 0.297 yellow white 0.010 white miniature 0.337

Accepted Answer

A) y m v w 
B) y w v m 
C) y m w v 
D) y w m v 
A) y m v w 
B) y w v m 
C) y m w v 
D) y w m v

Question 14

The theory of chromosomal inheritance was first proposed by

Accepted Answer

A) Mendel. 
B) Morgan. 
C) Knight. 
D) Sutton. 
A) Mendel. 
B) Morgan. 
C) Knight. 
D) Sutton.

Question 15

A 39-year-old woman is in her sixth week of pregnancy.Due to her advanced age, she is at higher risk for having a baby with Down's syndrome than younger pregnant women.She would like to find out as early as possible whether or not her baby has Down's syndrome.Her doctor should suggest

Accepted Answer

A) amniocentesis. 
B) genetic counseling. 
C) chorionic villi sampling. 
D) a pedigree analysis. 
A) amniocentesis. 
B) genetic counseling. 
C) chorionic villi sampling. 
D) a pedigree analysis.

Question 16

Suppose you are carrying out a series of crosses with an insect where the mechanism of sex determination is unknown.You discover a mutant female with short bristles and decide to cross it with a wild type male that has normal bristles.Half of the F1 progeny have short bristles but all of these short-bristled F1 progeny are males.Based on these results, a valid hypothesis would be

Accepted Answer

A) Males are ZW, females are ZZ, and short bristles are caused by a dominant allele on the Z chromosome. 
B) Males are ZZ, females are ZW, and short bristles are caused by a recessive allele on the Z chromosome. 
C) Males are ZZ, females are ZW, and short bristles are caused by a dominant allele on the W chromosome. 
D) Males are ZZ, females are ZW, and short bristles are caused by a dominant allele on the Z chromosome. 
A) Males are ZW, females are ZZ, and short bristles are caused by a dominant allele on the Z chromosome. 
B) Males are ZZ, females are ZW, and short bristles are caused by a recessive allele on the Z chromosome. 
C) Males are ZZ, females are ZW, and short bristles are caused by a dominant allele on the W chromosome. 
D) Males are ZZ, females are ZW, and short bristles are caused by a dominant allele on the Z chromosome.

Question 17

Which of the following will help you distinguish between the two final suspects?

Accepted Answer

A) single nucleotide polymorphisms (SNPs) 
B) human genome map 
C) linkage data 
D) markers on the Y chromosome 
A) single nucleotide polymorphisms (SNPs) 
B) human genome map 
C) linkage data 
D) markers on the Y chromosome

Question 18

In a two-point cross to map genes A and B, you obtained 98 recombinant types and 902 parental types among the offspring.How far apart are these genes?

Accepted Answer

A) 9.8 cM 
B) 0.98 cM 
C) 90.2 cM 
D) 9.02 cM 
A) 9.8 cM 
B) 0.98 cM 
C) 90.2 cM 
D) 9.02 cM

Question 19

A test cross can be used to do all of the following except

Accepted Answer

A) determine whether an individual that displays a dominant phenotype is homozygous for the trait. 
B) determine whether an individual that displays a dominant phenotype is heterozygous for the trait. 
C) gather genotype information from phenotype information. 
D) identify the chromosome on which a gene is located. 
A) determine whether an individual that displays a dominant phenotype is homozygous for the trait. 
B) determine whether an individual that displays a dominant phenotype is heterozygous for the trait. 
C) gather genotype information from phenotype information. 
D) identify the chromosome on which a gene is located.

Question 20

In Drosophila, the sex of an individual is determined by

Accepted Answer

A) 1 pair of alleles. 
B) the number of X chromosomes. 
C) the number of Y chromosomes. 
D) 1 pair of autosomes. 
A) 1 pair of alleles. 
B) the number of X chromosomes. 
C) the number of Y chromosomes. 
D) 1 pair of autosomes.

Exam 13: Chromosomes, Mapping, and the Meiosis-Inheritance Connection

What would be the results of a test cross with the F1 flies?

Given that these two gene loci are very closely linked, the genotypic ratio in the F2 generation should be closest to

Amniocentesis is a procedure that is normally used

Traits that are controlled by genes located on the X chromosome are said to be ________________.

In Drosophila, dosage compensation is controlled by the male-specific lethal (MSL) complex consisting of MSL proteins and roX RNAs.Based on what you know about dosage compensation, the role of the MSL complex in males would be to

In humans, if non-disjunction led to an individual with a genotype of XXY, that person would

A deletion of a particular stretch of chromosome 15 can cause either Prader-Willi syndrome or Angelman syndrome, depending on

How did the development of anonymous markers aid in the production of a human genetic map?

The classic experiments performed by Creighton and McClintock in Maize

Of the 23 pairs of human chromosomes, 22 pairs are homologous and are found in both males and females.These are called ________.

Huntington's disease is caused by a single dominant allele.It is a lethal disease, yet it persists in the human population.Which of the following statements best describes why?

Which offspring inherit all their mitochondrial DNA from their mother and none from their father?

The theory of chromosomal inheritance was first proposed by

A 39-year-old woman is in her sixth week of pregnancy.Due to her advanced age, she is at higher risk for having a baby with Down's syndrome than younger pregnant women.She would like to find out as early as possible whether or not her baby has Down's syndrome.Her doctor should suggest

Which of the following will help you distinguish between the two final suspects?

In a two-point cross to map genes A and B, you obtained 98 recombinant types and 902 parental types among the offspring.How far apart are these genes?

A test cross can be used to do all of the following except

In Drosophila, the sex of an individual is determined by

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What would be the results of a test cross with the F₁ flies?

Given that these two gene loci are very closely linked, the genotypic ratio in the F₂ generation should be closest to