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Snapdragons are flowers that come in a variety of colours, including red, pink, and white. A series of crosses wit snapdragons having flowers of different colours produced the following results: Pink × pink: 27 pink, 13 red, 14 white red × red: all red White × white: all white Pink × white: 29 pink, 26 white pink × red: 28 pink, 27 red white × red: all pink Based on the results, what is the most reasonable explanation for the inheritance of these flower colours?


A) qualitative effects
B) pleiotropic effects
C) incomplete dominance
D) codominance
E) more than two alleles

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In tigers, a recessive allele causes a white tiger absence of fur pigmentation) . If two phenotypically normal tigers that are heterozygous at this locus are mated, what percentage of their offspring is expected to be white?


A) 50%
B) 75%
C) about 90%
D) 25%
E) about 66%

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In humans, ABO blood types refer to glyocproteins in the membranes of red blood cells. There are three alleles for this autosomal gene: IA, IB, and i. The IA allele codes for the A glycoprotein, the IB allele codes for the B glycoprotein, and the i allele doesn't code for any membrane glycoprotein. IA and IB are codominant, and i is recessive to both IA and IB. People with A type blood have the genotypes IAIA or IAi, people with type B blood are IBIB or IBi, people with type AB blood are IAIB, and people with O type blood are ii. If a woman with type AB blood marries a man with type O blood, which of the following blood types could their children possibly have?


A) A and B
B) AB and O
C) A, B, and O
D) A, B, and AB
E) A, B, AB, and O

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Different ratios occur in crosses with single gene pairs or two gene pairs. What types of ratios are likely to occur in crosses dealing with a single gene pair?


A) 3:1, 1:1, 1:2:1
B) 9:7, 12:3:1
C) 1:1:1:1, 1:4:6:4:1
D) 9:3:3:1, 1:2:1
E) 15:1, 1:2

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Regarding an allelic pair for flower colour in snapdragons, heterozygotes have pink flowers, whereas the two homozygotes have red flowers or white flowers. When plants with red flowers are crossed with plants with white flowers, what proportion of the offspring is expected to have pink flowers?


A) 50%
B) 100%
C) 0%
D) 25%
E) 75%

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A couple has a child with Harman's ataxia a recessive disorder) . If this couple has second child, what is the probability that child will have ataxia?


A) 2/3
B) 0
C) 1/2
D) 1/16
E) 1/4

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In humans, blue eyes are inherited as a recessive autosomal trait and colour blindness is an X- linked recessive trait. A woman with blue eyes and normal colour vision whose father was colour blind marries a man who also has normal colour vision. He has brown eyes, but his mother had blue eyes. Which of the following do you expect to be true for their sons?


A) Their sons will all have normal colour vision and brown eyes.
B) Their sons will all have normal colour vision and blue eyes.
C) One- half of their sons will have normal colour vision and brown eyes; 1/2 of their sons will have normal colour vision and blue eyes.
D) One- fourth of their sons will be colour blind and have blue eyes, 1/4 of their sons will be colour blind and have brown eyes, 1/4 of their sons will have normal colour vision and blue eyes, 1/4 of their sons will have normal colour vision and brown eyes.
E) One- half of their sons will be colour blind and have blue eyes; 1/2 their sons will be colour blind and have brown eyes.

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Suppose two AaBbCc individuals are mated. Assuming that the genes are not linked, what fraction of the offspring are expected to be homozygous recessive for the three traits?


A) 1/8
B) 1/256
C) 1/64
D) 1/4
E) 1/16

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Gene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cactuses have dull spines. At the same time, a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn cactuses have no spines at all. A cross between a true- breeding sharp- spined cactus and a spineless cactus would produce


A) 50 percent sharp- spined, 50 percent dull- spined progeny.
B) 25 percent sharp- spined, 50 percent dull- spined, and 25 percent spineless progeny.
C) all sharp- spined progeny.
D) all spineless progeny.
E) It is impossible to determine the phenotypes of the progeny.

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Assuming independent assortment for all gene pairs, what is the probability that the following parents, AABbCc × AaBbCc, will produce an AaBbCc offspring?


A) 9/16
B) 1/8
C) 3/4
D) 1/2
E) 1/16

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What is the probability that a gamete from an individual with the genotype E1E2X1X1A1A2M2M2 will contain all paternally derived homologues?


A) 1/6
B) 1/16
C) 1/4
D) 1/8

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The figure provided shows the pedigree for a family. Dark- shaded symbols represent individuals with one of the two major types of colon cancer. Numbers under the symbols are the individual's age at the time of diagnosis. Males are represented by squares, females by circles. The figure provided shows the pedigree for a family. Dark- shaded symbols represent individuals with one of the two major types of colon cancer. Numbers under the symbols are the individual's age at the time of diagnosis. Males are represented by squares, females by circles.   From this pedigree, this trait seems to be inherited A)  from mothers. B)  as an autosomal dominant. C)  as an autosomal recessive. D)  as a result of epistasis. E)  as an incomplete dominant. From this pedigree, this trait seems to be inherited


A) from mothers.
B) as an autosomal dominant.
C) as an autosomal recessive.
D) as a result of epistasis.
E) as an incomplete dominant.

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  Figure 14.3 -The distance between two genes is a determinant of their recombination frequency. Based on the image below, which of the following sets of genes will show the greatest recombination frequency? A)  A and B B)  C and D C)  A and E D)  B and C Figure 14.3 -The distance between two genes is a determinant of their recombination frequency. Based on the image below, which of the following sets of genes will show the greatest recombination frequency?


A) A and B
B) C and D
C) A and E
D) B and C

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  Figure 14.2 -In the figure above, flower A was crossed with flower B to produce flower C. The phenotype of flower C is the result of A)  aneuploidy. B)  codominance. C)  the passing on of a sex- linked trait. D)  incomplete dominance. Figure 14.2 -In the figure above, flower A was crossed with flower B to produce flower C. The phenotype of flower C is the result of


A) aneuploidy.
B) codominance.
C) the passing on of a sex- linked trait.
D) incomplete dominance.

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Radish flowers may be red, purple, or white. A cross between a red- flowered plant and a white- flowered plant yields all- purple offspring. The part of the radish we eat may be oval or long, with long being the dominant trait. If true- breeding red long radishes are crossed with true- breeding white oval radishes, the F1 will be expected to be which of the following?


A) red and long
B) purple and oval
C) purple and long
D) red and oval
E) white and long

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Two individuals of genotype AABBCCDD and aabbccdd are mated. The F1 generation is interbred self- fertilized) to yield 5000 progeny. What proportion of the F2 is expected to be AabbCcDD?


A) 1/2
B) 1/78
C) 1/64
D) 1/8

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A man and woman are both of normal pigmentation, but both have one parent who is albino without melanin pigmentation) . Albinism is an autosomal not sex- linked) recessive trait. What is the probability that their first female child will have albinism?


A) 0%
B) 1/8
C) 1/2
D) 1/4
E) 100%

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A sexually reproducing animal has two unlinked genes, one for head shape H) and one for tail length T) . Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism?


A) tt
B) T
C) HhTt
D) HT
E) Hh

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Hemophilia is caused by several genetic factors; one, a recessive allele of an X- linked gene, is the subject of this problem. Assume that a man with hemophilia marries a normal woman whose father had hemophilia. What is the probability that their first son will have hemophilia?


A) 1/2
B) 1/4
C) 3/4
D) 1/16
E) 1/8

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A heterozygous, but phenotypically wild- type fruit fly gray body colour and normal wings) was mated to a black fly with vestigial wings. The offspring had the following phenotypic distribution: wild type, 720; Black- vestigial, 780; black- normal, 280; gray- vestigial, 220. What conclusion is likely from these results?


A) Epistasis has modified a 9:3:3:1 ratio.
B) The black and vestigial loci are linked.
C) The black and vestigial loci are allelic.
D) The black and vestigial loci assort independently from each other.

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