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  -What is an adaptive advantage of recombination between linked genes? A) Recombination is required for independent assortment. B) Recombination must occur or genes will not assort independently. C) New allele combinations are acted upon by natural selection. D) The forces on the cell during meiosis II results in recombination. E) Recombination ensures genes far away from each other are inherited together. -What is an adaptive advantage of recombination between linked genes?


A) Recombination is required for independent assortment.
B) Recombination must occur or genes will not assort independently.
C) New allele combinations are acted upon by natural selection.
D) The forces on the cell during meiosis II results in recombination.
E) Recombination ensures genes far away from each other are inherited together.

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A homozygous tomato plant with red fruit and yellow flowers was crossed with a homozygous tomato plant with golden fruit and white flowers.The F₁ all had red fruit and yellow flowers.The F₁ were testcrossed by crossing them to homozygous recessive individuals and the following offspring were obtained: Red fruit and yellow flowers-41 Red fruit and white flowers-7 Golden fruit and yellow flowers-8 Golden fruit and white flowers-44 How many map units separate these genes?


A) 17.6
B) 15
C) 17.1
D) 18.1
E) 3

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Glucose-6-phosphate dehydrogenase deficiency (G6PD) is inherited as a recessive allele of an X-linked gene in humans.A woman whose father suffered from G6PD marries a normal man. (a) What proportion of their sons is expected to be G6PD? (b) If the husband was not normal but was G6PD deficient,would you change your answer in part (a) ?


A) (a) 100%; (b) no
B) (a) 1/2; (b) yes
C) (a) 1/2; (b) no
D) (a) zero; (b) no
E) (a) 100%; (b) yes

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A nonreciprocal crossover causes which of the following products?


A) deletion only
B) duplication only
C) nondisjunction
D) deletion and duplication
E) duplication and nondisjunction

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  -The pedigree in the figure above shows the transmission of a trait in a particular family.Based on this pattern of transmission,the trait is most likely A) mitochondrial. B) autosomal recessive. C) sex-linked dominant. D) sex-linked recessive. E) autosomal dominant. -The pedigree in the figure above shows the transmission of a trait in a particular family.Based on this pattern of transmission,the trait is most likely


A) mitochondrial.
B) autosomal recessive.
C) sex-linked dominant.
D) sex-linked recessive.
E) autosomal dominant.

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The term hemizygous refers to


A) autosomal characteristics in diploid populations.
B) incomplete dominance of phenotypic traits.
C) having two different alleles on the loci of polyploidal species.
D) X-linked characteristics expressed in mammalian males.
E) X-linked characteristics in mammalian females resulting from Barr body silencing.

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Cinnabar eyes is a sex-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) 0%
B) 25%
C) 50%
D) 75%
E) 100%

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A phenotypically normal prospective couple seeks genetic counselling because the man knows that he has a translocation of a portion of his chromosome 4 that has been exchanged with a portion of his chromosome 12.Although he is normal because his translocation is balanced,he and his wife want to know the probability that his sperm will be abnormal.What is your prognosis regarding his sperm?


A) 1/4 will be normal, 1/4 will have the translocation, and 1/2 will have duplications and deletions.
B) All will carry the same translocation as the father.
C) None will carry the translocation since abnormal sperm will die.
D) His sperm will be sterile and the couple might consider adoption.
E) 1/2 will be normal and the rest will have the father's translocation.

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Pseudohypertrophic muscular dystrophy is a human disorder that causes gradual deterioration of the muscles.Only boys are affected,and they are always born to phenotypically normal parents.Due to the severity of the disease,the boys die in their teens.What can we deduce about the disorder?


A) dominant allele, sex-linked
B) recessive allele, autosomal
C) recessive allele, sex-linked
D) incomplete allele dominant, sex-linked
E) multiple alleles, autosomal

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Refer to the following information to answer the questions below. A man who is an achondroplastic dwarf with normal vision marries a colour-blind woman of normal height.The man's father was 6 feet tall,and both the woman's parents were of average height.Achondroplastic dwarfism is autosomal dominant,and red-green colour blindness is X-linked recessive. -What proportion of their sons would be colour-blind and of normal height?


A) none
B) half
C) one out of four
D) three out of four
E) all

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Of the following human aneuploidies,which is the one that generally has the most severe impact on the health of the individual?


A) 47, +21
B) 47, XXY
C) 47, XXX
D) 47, XYY
E) 45, X

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What is the greatest benefit of having used a testcross for this experiment?


A) The homozygous recessive parents are obvious to the naked eye.
B) The homozygous parents are the only ones whose crossovers make a difference.
C) Progeny can be scored by their phenotypes alone.
D) All of the progeny will be heterozygous.
E) The homozygous recessive parents will be unable to cross over.

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Which of the following is known as a Philadelphia chromosome?


A) a human chromosome 22 that has had a specific translocation
B) a human chromosome 9 that is found only in one type of cancer
C) an animal chromosome found primarily in the mid-Atlantic area of the United States
D) an imprinted chromosome that always comes from the mother
E) a chromosome found not in the nucleus but in mitochondria

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Which of the following produces a Mendelian pattern of inheritance?


A) genomic imprinting
B) a mitochondrial gene mutation
C) a chloroplast gene mutation
D) viral genomes that inhabit egg cytoplasm
E) a trait acted upon by many genes

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Which of the following is true of aneuploidies in general?


A) A monosomy is more frequent than a trisomy.
B) 45 X is the only known human live-born monosomy.
C) Some human aneuploidies have selective advantage in some environments.
D) Of all human aneuploidies, only Down syndrome is associated with mental retardation.
E) An aneuploidy resulting in the deletion of a chromosome segment is less serious than a duplication.

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Red-green colour blindness is a sex-linked recessive trait in humans.Two people with normal colour vision have a colour-blind son.What are the genotypes of the parents?


A) XcXc and XcY
B) XcXc and XCY
C) XCXC and XcY
D) XCXC and XCY
E) XCXc and XCY

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  -What is the definition of one map unit? A) the physical distance between two linked genes B) a 1% frequency of recombination between two genes C) 1 nanometer of distance between two genes D) the recombination frequency between two genes assorting independently E) 1 picometer of distance between two genes -What is the definition of one map unit?


A) the physical distance between two linked genes
B) a 1% frequency of recombination between two genes
C) 1 nanometer of distance between two genes
D) the recombination frequency between two genes assorting independently
E) 1 picometer of distance between two genes

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Which of the following is the meaning of the chromosome theory of inheritance as expressed in the early 20th century?


A) Individuals inherit particular chromosomes attached to genes.
B) Mendelian genes are at specific loci on the chromosome and in turn segregate during meiosis.
C) Homologous chromosomes give rise to some genes and crossover chromosomes to other genes.
D) No more than a single pair of chromosomes can be found in a healthy normal cell.
E) Natural selection acts on certain chromosome arrays rather than on genes.

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  -In a series of mapping experiments,the recombination frequencies for four different linked genes of Drosophila were determined as shown in the above figure.What is the order of these genes on a chromosome map? A) rb-cn-vg-b B) vg-b-rb-cn C) cn-rb-b-vg D) b-rb-cn-vg E) vg-cn-b-rb -In a series of mapping experiments,the recombination frequencies for four different linked genes of Drosophila were determined as shown in the above figure.What is the order of these genes on a chromosome map?


A) rb-cn-vg-b
B) vg-b-rb-cn
C) cn-rb-b-vg
D) b-rb-cn-vg
E) vg-cn-b-rb

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In cats,black fur colour is caused by an X-linked allele; the other allele at this locus causes orange colour.The heterozygote is tortoiseshell.What kinds of offspring would you expect from the cross of a black female and an orange male?


A) tortoiseshell females; tortoiseshell males
B) black females; orange males
C) orange females; orange males
D) tortoiseshell females; black males
E) orange females; black males

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