Ch.15 - Chromosomal Theory of InheritanceWorksheetSee all chapters
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Ch.1 - Introduction to Biology
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Ch.15 - Chromosomal Theory of Inheritance
Ch.16 - DNA Synthesis
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Ch.55 - Conservation Biology

Concept #1: Chromosomal Theory of Inheritance

Concept #2: Morgan's Experiments and Sex-Linkage

Concept #3: Dosage Compensation and X-Inactivation

Concept #4: Recombination and Genetic Maps

Additional Problems
The X chromosome is:  a. Larger than the Y chromosome b. Smaller than the Y chromosome c. The same size as the Y chromosome d. Genetically identical to the Y chromosome e. Both A and D are correct
The Y chromosome is:  a. Larger than the X chromosome b. Contains more genes than the X chromosome c. The same size as the X chromosome d. Smaller than the X chromosome e. Genetically identical to the X chromosome
People who have a single X chromosome are female, while those with XXY sex chromosomes are males. In order to be a female a human:  a. Must have two X chromosomes b. Cannot have a Y chromosome c. Must have one X chromosome d. Must have one Y chromosome e. Cannot have an X chromosome
In humans, alleles are inherited from:  a. Females only (moms) b. Males only (dads) c. Males and females (one allele from each parent) d. Males and females (two alleles from each parent) e. None are correct
The most common phenotype or allele for a gene in a population is referred to as:  a. The wild type b. The dominant population c. The recessive population d. The P generation e. The F1 generation
Linked genes, by definition, are genes that: a. Are found on the same chromosome b. Have no alleles c. Are found in the same species d. Have more alleles than usual e. Are alleles that are found in different daughter cells
The pair of unmatched chromosomes in humans:  a. Are the sex chromosomes b. Are the "X" and "Y" chromosomes c. Determine sex (gender) of humans d. Contain different genes e. All are correct
Diagrams of gene order and spacing on chromosomes are:  a. Karyotypes b. Phenotypes c. Linkage maps d. Genotypes e. Metabolic maps
A male expresses:  a. Only the dominant alleles on his X chromosome b. Both the dominant and recessive alleles on his X chromosome c. Only the homozygous recessive alleles on his X chromosome d. None of the alleles on his X chromosome e. None of these are correct
A Barr body is:  a. An inactive Y chromosome b. An inactive autosome c. An active X chromosome d. An active Y chromosome e. An inactive X chromosome
Linkage maps are diagrams of nitrogen base sequences on DNA.  a. True b. False
X-linked recessive disorders affect more females than males. a. True b. False
A male expresses an X-linked recessive disorder only if he inherits these alleles from both parents.  a. True b. False
The chromosomal designation for a human male is:  a. XX b. XO c. XY d. YY e. XXX
The chromosomal designation for a human female is:  a. XYY b. XY c. YY d. XX e. None are correct
In humans, the sex of a child is determined by:  a. The sex chromosome in the egg b. The number of autosomes in the sperm c. The number of autosomes in the egg d. The sex chromosome in the sperm  
Recombinant chromosomes have a mix of paternal and maternal alleles due to: a. Random fertilization b. Linkage c. Independent assortment d. Crossing over e. Mutation
Crossing over is more likely to separate genes on a chromosome if they are:a. Close togetherb. Far apartc. Recessive genesd. Dominant genese. Mutated genes
What characteristic is exhibited by an X-linked trait?a. Only females have the trait.b. Males inherit X-linked traits from their paternal parent only.c. Females inherit X-linked traits from their maternal parent only.d. Males can inherit a gene for an X-linked trait from either parent but normally inherit it from their fathers.e. Females can inherit a gene for an X-linked trait from either parent.
In chickens and other birds, the chromosomal basis of inheritance is the opposite of that in humans; i.e., in birds, ZZ homogametic individuals are males , and ZW heterogametic individuals are females .In chickens, barred plumage is dominant to non-barred plumage; the gene is Z-linked.Suppose that you were a poultry breeder and that you needed large numbers of  barred males and nonbarred females . Describe a breeding stock that you could assemble for this purpose, which would produce only barred males and nonbarred females.Be certain that you show the genotypes of both the roosters and the hens in your breeding stock and also the genotypes of all the offspring that this stock will yield.
A particular inherited abnormality in humans has been shown to be an X-linked recessive trait. In one family seeking professional help from a genetic counselor, the following information is known:1. The mother shows the abnormality.2. Their only child is a daughter who is normal.i) If their next child is a son, what is the probability that he will show the abnormality?ii) What is the probability that the next child born will be a daughter showing the abnormality?
All female mammals have one active X chromosome per cell instead of two. What causes this to happen?a. attachment of methyl (-CH3) groups to the X chromosome that will remain activeb. activation of the XIST gene on the X chromosome that will become the Barr bodyc. inactivation of the XIST gene on the X chromosome derived from the male parentd. activation of the BARR gene on one X chromosome, which then becomes inactive
You are given a mouse with short ears and a straight tail from a pure breeding strain and another mouse with long ears and a curly tail, also from a pure breeding strain. When you cross them the offspring all have short ears and straight tails. When you cross these offspring to one another the results in the next generation exhibit all four possible combinations of ear size and tail shape (short & straight, long & curly, short & curly, long & straight) with short and straight being the most common and long and curly being the least common.If you wanted to test for linkage which of the following types of mice would you use in a test cross with the second generation?a. homozygous for straight tail and short earb. homozygous for curly tail and long earc. homozygous for short tail and long eard. homozygous for curly tail and short eare. heterozygous for both
Thomas Hunt Morgan chose to work with fruit flies in part because they have a short life cycle and large number of offspring.  a. True b. False
Assume fruit flies have the same sex-determining system as humans. Cinnabar eyes is an X-linked recessive characteristic in fruit flies. If a female having cinnabar eyes is crossed with a wild-type male, what percentage of the F1 males will have cinnabar eyes?A) 50%B) 0%c) 75%D) 100%E) 25%
Assume moths have the same sex-determining system as humans. In a species of moth, red wings are caused by an X-linked allele; the other allele at this locus causes white wings. The heterozygote has "candy-cane" wings that are white with red stripes. What kinds of offspring would you expect from the cross of a red female and a white male?a. white females; red malesb. candy-cane females; red malesc. red females; white malesd. white females; white malese. candy-cane females; candy-cane males
Color blindness is a sex-linked recessive. A girl with normal vision whose, father was colorblind, marries a colorblind man. What will be the genotypes and phenotypes of their children?
Could a colorblind man pass his gene for colorblindness on to his sons? Show the cross or crosses to support your answer. What would be the genotype of a wife (for this man) that would produce only normal visioned sons? Show the cross or crosses to support your answer. Could this man find a wife that would result in daughters that would not carry the gene for color blind vision? Show the cross or crosses to support your answer.
A woman with normal blood clotting factor had a hemophiliac father. If she begins a family with a man whose mother was a hemophiliac, then what is the probability that they will have a hemophiliac son and a hemophiliac daughter?a. 1/2b. 1/4c. 1/8d. 1/16e. 1/64
Sex chromosomes in birds are referred to as “W” and “Z”, with females being the heterogametic sex and males being homogametic for the Z chromosome. In chickens, the allele for feather color is Z-linked with black feathers dominant to red feathers. If a rooster that is heterozygous for black feathers mates with a red hen, what is the probability that their chicks will be red hens?a. 1/4b. 1/2c. zerod. 1/1e. 1/18
Which of the following statements is true regarding linkage mapping?A. Linkage mapping can be used to determine the exact distance between genes found on the same chromosome.B. Linkage mapping can be used to determine the relative distance between genes found on the same chromosome.C. Linkage mapping is a method used to determine when a recombination event is likely to occur on a particular chromosome.D. In a linkage map, the distance between genes is measured in base pairs.
Two parents of genotype AAcc, aaCC are crossed (i.e. AAcc x aaCC). Neither locus is sex-linked. The A and C loci are on different chromosomes. a) Give the expected resulting genotypic frequencies for F1 offspring.b) Now give the expected genotypic frequencies for an F1 cross.
A true-breeding red-eye female is crossed with a white-eye male, you expect _____ red eye females that are heterozygous (consider in your % the number of males and females)A. 25%B. 50%C. 100%D. 0%
Color-blindness is an X-linked recessive disorder. Mike is color-blind. His wife, Meg, is homozygous for the normal color vision allele. Using Punnet squares, derive and compare the genotypic and phenotypic ratios expected for the offspring of this marriage.If they have eight children, how many of them would you expect to be color-blind?
What is the chromosomal theory of inheritance?
The following pedigree depicts the inheritance of a hereditary disease affecting the heart. What is the most likely mode of inheritance of this disease? Pay particular attention to individuals 10 & 11.A. autosomal dominantB. autosomal recessiveC. X-linked recessiveD. Y-linkedE. X-linked dominant
A mutation that causes a yellowing of leaves in snapdragon plants was discovered in the early 1900s. Plants with this condition, termed aurea, have less chlorophyll than green plants. Crosses between various combinations of green and aurea plantsyielded the following results:green x green = all greenaurea x aurea = 2/3 green, 1/3 aureagreen x aurea = 1/2 green, 1/2 aureaIf the green allele is designated as G, and the aurea allele is designates as GA, assign genotypes to the phenotypes listed.GGGAGAGGA
A man homozygous for sickle cell disease (an autosomal recessive disease, i.e. not sex linked) who has normal vision marries a woman heterozygous for sickle cell disease who is colorblind (a recessive X-linked condition). What is the chance that a child (of either sex) born to them will have both sickle cell disease and be colorblind.A. 0B. 1/2C. 3/8D. 1/4E. 1/8
A black female cat (XBXB) and an orange male cat (XOY) were mated to each other ad produced a male cat that was calico. Which sex chromosomes did this male offspring inherit from its mother and father? Remember that the presence of the Y chromosome determines maleness in mammals.
Predict the frequency of progeny genotypes for the cross: XAXaBb x XaYbb.
Queen Victoria of England was believed to have been a carrier for Hemophilia. She married Prince Albert who was not a hemophiliac. Their chances of having a male heir to the throne who was not a hemophiliac were?A. 100%B. 0%C. 25%D. 50%
Human sex chromosomes, X and Y, _____.A. Have the same lociB. carry the same number of genesC. are homologous only at the pseudo-autosomal regionsD. only carry sex genes
Drosophila may be monosomic for chromosome 4, yet remain fertile. A recessive mutant for bent bristles is identified on chromosome 4. Determine the genotypes of the F1 and F2 progeny for the following crosses. The following cross is conductd of true-breeding adult flies: monosomic normal bristles x diploid bent bristlesSelect the two F1 genotypes that will be produced from this cross.A. _/b+B. _/bC. b/bD. b/b+E. b+/b+
Which approach to determining the likelihood of various genotypes occurring in the offspring of particular parents is easier for you-constructing a Punnett square, or using the product rule to calculate probabilities? Compare and contrast the inheritance patterns of autosomal recessive and autosomal dominant traits.
Which ofthe following is required for chromatin to condense into the 30nm fiber?A. histone H1B. chromosomal scaffolding proteinsC. histone tails extending from the nucleosomeD. histone H1 & histone tails extending from the nucleosome.
_____ is though to be composed of _____.A. The active X chromosome; heterochromatinB. A Barr body; euchromatinC. The centromere; euchromatinD. A telomere; euchromatinE. All of the above are correct answersF. None of the above is a correct answer
Which of the following statements is TRUE of linkage?A. All of the traits that Mendel studied - seed color, pod shape, flower color, and others - are due to genes linked on the same chromosome.B. Crossing over has a low chance of separating genes that are located very close together on the same chromosome.C. The farther two genes are apart on a chromosome, the lower the probability that a crossover will occur between them.D. Linked genes are found on different chromosomes.E. The observed frequency of recombination of two genes that are far apart from each other has a maximum value of 100%.
The state of having more than two sets of chromosomes is called _____.A. aneuploidB. dominantC. non-disjunctionD. polyploidE. autosomal
Wildtype fruit flies have gray bodies (b+) and red eyes (cn+) while mutant fruit flies have black bodies (b) and cinnabar eyes (cn). A parental (P) cross is performed between a true-breeding gray-bodied red eye fruit fly and a true-breeding black-bodied cinnabar eye fruit fly. What is the genotype and phenotype of the F1 flies?
In cats, black fur color is caused by an X-linked allele, the other allele at this locus causes orange color. The heterozygote is a tortoiseshell. What kinds of offspring would you expect from the cross of an orange female and a black male?A. orange females, black malesB. orange females, orange malesC. tortoiseshell females, orange malesD. tortoiseshell females, black malesE. black females, orange males
Assume that white color (W) is dominant over yellow color (w) in corn. Perform a Punnett square for a cross where pollen from the anthers of a plant is heterozygous for color is placed on the pistil of a yellow-fruited plant. What are the genotypes and phenotypes you would expect to find from this cross?
Cinnabar eyes is a sex-linked recessive characteristic in fruit flies. If a male having cinnabar eyes is crossed with a wild-type female, what percentage of the F1 males will have cinnabar eyes?A. 0%B. 25%C. 50%D. 75%E. 100%
Protein function is subject to post-translational regulation. Which of the following amino acids is enriched in histones and is modified through methylation or acetylation?A. AB. BC. C and DD. D
Red-green color blindness is a recessive sex-linked trait (i.e. it is on the X chromosome). If a color blind man marries a woman with normal vision, what are their children likely to be?A. All the boys and all the girls will e color blind.B. Half of the boys and none of the girls will be color blind.C. Half of the girls and none of the boys will be color blind.D. None of the children will be color blind.E. None of the answers listed above are correct.
Analyze the genotypes and phenotypes shown in the Punnet square below. Choose the term that describes the expression of the F gene.A. Sex-linkedB. PleiotropyC. Incomplete dominanceD. Polygenic traitE. CodominanceF. Linked genesG. Homozygous recessive
You do a cross between a white curly haired mouse and a black straight-haired mouse. You do not know if these animals come from true breeding populations. The 16 F1 progeny are 8 white curly mice and 8 black straight-haired mice. The following are consistent with this data.A. Black is dominant.B. One of the mice was heterozygous for both curly/straight and white/black hair.C. Both curly/straight and white/black are present together on the same chromosome.D. All of the answers listed above are correct.E. None of the answers listed above are correct.
Give the genotypes of the various individuals in the pedigree shown below (Figure 8.1). Show the alleles as superscripts to the X chromosomes, with H representing the normal allele and h the allele for hemophilia.NOTE: Circles represent females, squares represent males, black squares represent hemophiliacs
Independent assortment of chromosomes is a result of A. the random nature of fertilization of ova by sperm.B. the random separation of the sister chromatids to the two daughter cells during anaphase II.C. the random orientation of each homologous pair at the metaphase I.D. the relatively small degree of homology shared by the X and Y chromosomes.E. all of the above
Why are recessive X-linked traits seen more in human males than in human females? Select all that apply.A. Males have an X chromosome, but females do not.B. Actually, X-linked traits are seen more often in females than in males, because they have two X chromosomes.C. Males don't have a second X chromosome to mask the effects of the first one.D. This phenomenon is due to X-inactivation.E. While females would need two of these alleles to express the recessive phenotype, males only need one.F. Sperm are more likely to carry an X chromosome than a Y chromosome.
Study the image shown below. Which of the following statements are true?A. Sister chromatids always have the same alleles.B. These homologous chromosomes have different alleles.C. Gene A is at the same locus on all four chromatids.D. Allele A has two genes.
Normally in humans a mutant gene on the Y chromosome will be inherited in which of the following ways?A. All of the daughters of a parent with the mutant gene will receive it but none of the sons will.B. All of the sons of a parent with the mutant gene will receive it but none of the daughters will.C. Half of the sons of a parent with the mutant gene will receive it and half will not; none of the daughters will receive it.D. One-quarter of both the sons and daughters of a parent with the mutant gene will receive it and the rest will not.E. Half of the sons and daughters of a parent with the mutant gene will receive it and half will not.
In a species of snakes, two parents of genotype Aa are crossed together (Aa x Aa). The locus is not sex-linked.Assume complete dominance of the alleles, with AA and Aa causing a jagged scale pattern, and aa causing a smooth scale phenotype.Give the expected genotypic and phenotypic frequencies of the offspring.
In Drosophila melanogaster, the white-eye mutation is _____ and is represented as _____ for a white eye female.A. gender-linked recessive; w+w+B. gender-linked dominant, wwC. gender-linked dominant, w+w+D. gender-linked recessive, ww
What is wild type (WT)?A. A gene that has not been manipulated or mutated.B. A gene that has been modified to spread through populations quickly.C. A gene with a deletion to make it inactive.D. A gene that has been targeted by RNAi to make it inactive.