ND STONY BROOK UNIVERSITY LOOSELEAF GENETICS: FROM GENES TO GENOMES
6th Edition
ISBN: 9781260406092
Author: HARTWELL, Leland, HOOD, Leroy, Goldberg, Michael
Publisher: Mcgraw-hill Education/stony Brook University
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Textbook Question
Chapter 5, Problem 2P
a. | A Drosophila male from a true-breeding stock with scabrous eyes was mated with a female from a true-breeding stock with javelin bristles. Both scabrous eyes and javelin bristles are autosomal recessive mutant traits. The F1 progeny all had normal eyes and bristles. F1 females from this cross were mated with males with both scabrous eyes and javelin bristles. Write all the possible |
b. | The cross in part (a) yielded the following progeny: 77 scabrous eyes and normal bristles; 76 wild type (normal eyes and bristles); 74 normal eyes and javelin bristles; and 73 scabrous eyes and javelin bristles. Are the genes governing these traits likely to be linked, or do they instead assort independently? Why? |
c. | Suppose you mated the F1 females from the cross in part (a) to wild-type males. Why would this cross fail to inform you whether the two genes are linked? |
d. | Suppose you mated females from the true-breeding stock with javelin bristles to males with scabrous eyes and javelin bristles. Why would this cross fail to inform you whether the two genes are linked? |
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IN DROSOPHILA, AN X-LINKED
RECESSIVE MUTATION, Xm CAUSES
MINIATURE WINGS. LIST
THE F₂ PHENOTYPIC RATIOS IF:
A MINIATURE-WINGED FEMALE IS
CROSSED WITH A NORMAL MALE AND
A MINIATURE-WINGED MALE IS
●
●
CROSSED WITH A NORMAL FEMALE.
WHAT WOULD THE PHENOTYPIC RATIO
FROM (A) BE IF THE MINIATURE-
WINGED GENE WERE AUTOSOMAL?
ASSUME IN ALL CASES THAT THE P1
INDIVIDUALS ARE TRUE-BREEDING.
In Drosophila, an X-linked recessive mutation, (s) causes irregular wing margins. Give the genotypes,
phenotypes and phenotypic ratio of the F1 and F2 offspring in the following crosses
a. scalloped female crossed with a normal male
b. scalloped male crossed with a homozygous normal female.
Compare these results to those that would be obtained if the scalloped gene is autosomal.
a. In Drosophila, crosses between F1 heterozygotes ofthe form A b / a B always yield the same ratio ofphenotypes in the F2 progeny regardless of the distance between the two genes (assuming completedominance for both autosomal genes). What is thisratio? Would this also be the case if the F1 heterozygotes were A B / a b? (Hint: Remember that inDrosophila, recombination does not take placeduring spermatogenesis.)b. If you intercrossed F1 heterozygotes of the formA b / a B in mice, the phenotypic ratio among the F2progeny would vary with the map distance betweenthe two genes. Is there a simple way to estimate themap distance based on the frequencies of the F2phenotypes, assuming rates of recombination areequal in males and females? Could you estimatemap distances in the same way if the mouse F1heterozygotes were A B / a b?
Chapter 5 Solutions
ND STONY BROOK UNIVERSITY LOOSELEAF GENETICS: FROM GENES TO GENOMES
Ch. 5 - Choose the phrase from the right column that best...Ch. 5 - a. A Drosophila male from a true-breeding stock...Ch. 5 - Prob. 3PCh. 5 - The Punnett square in Fig. 5.4 shows how Mendels...Ch. 5 - In mice, the dominant allele Gs of the X-linked...Ch. 5 - In Drosophila, males from a true-breeding stock...Ch. 5 - If the a and b loci are 20 m.u. apart in humans...Ch. 5 - CCDD and ccdd individuals were crossed to each...Ch. 5 - In mice, the autosomal locus coding for the...Ch. 5 - In a particular human family, John and his mother...
Ch. 5 - Albino rabbits lacking pigment are homozygous for...Ch. 5 - In corn, the allele A allows the deposition of...Ch. 5 - If the a and b loci are 40 cM apart and an AA BB...Ch. 5 - Write the number of different kinds of phenotypes,...Ch. 5 - A DNA variant has been found linked to a rare...Ch. 5 - Figure 5.7a shows chromosomes during prophase of...Ch. 5 - Figure 5.7b shows bivalents in mouse primary...Ch. 5 - Cinnabar eyes cn and reduced bristles rd are...Ch. 5 - In Drosophila, the autosomal recessive dp allele...Ch. 5 - From a series of two-point crosses, the following...Ch. 5 - Map distances were determined for four different...Ch. 5 - In the tubular flowers of foxgloves, wild-type...Ch. 5 - In Drosophila, the recessive allele mb of one gene...Ch. 5 - A snapdragon with pink petals, black anthers, and...Ch. 5 - In Drosophila, three autosomal genes have the...Ch. 5 - Drosophila females heterozygous for each of three...Ch. 5 - Male Drosophila expressing the autosomal recessive...Ch. 5 - a. In Drosophila, crosses between F1 heterozygotes...Ch. 5 - A true-breeding strain of Virginia tobacco has...Ch. 5 - Prob. 30PCh. 5 - The following list of four Drosophila mutations...Ch. 5 - Do the data that Mendel obtained fit his...Ch. 5 - Two genes control color in corn snakes as follows:...Ch. 5 - A mouse from a true-breeding population with...Ch. 5 - Neurospora of genotype a c are crossed with...Ch. 5 - A cross was performed between one haploid strain...Ch. 5 - Prob. 40PCh. 5 - Prob. 41PCh. 5 - Indicate the percentage of tetrads that would have...Ch. 5 - Prob. 43PCh. 5 - This problem leads you through the derivation of a...Ch. 5 - a. In ordered tetrad analysis, what is the maximum...Ch. 5 - Prob. 46PCh. 5 - A single yeast cell placed on a solid agar will...Ch. 5 - Figure 5.29 shows mitotic recombination leading to...Ch. 5 - A diploid strain of yeast has a wild-type...Ch. 5 - In Drosophila, the yellow y gene is near the...Ch. 5 - Neurofibromas are tumors of the skin that can...Ch. 5 - Two important methods for understanding the...
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