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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Chapter 3, Problem 46P
This problem illustrates why classical geneticists in the days before DNA analysis usually needed to work with traits showing complete penetrance. Consider the sweet peas shown in Fig. 3.15, where the A– B– genotypic class normally produces purple flowers and all other genotypic classes have white flowers.
| a. | If the parental generation is
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| b. | Suppose now that only 75% of A– B– individuals have purple flowers (that is, the penetrance of this trait is 75%). What phenotypic ratio do you now expect among the F2 plants? |
| c. | In doing these types of crosses, what kinds of results (other than an unexpected F ratio) might suggest that penetrance of the purple |
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A test cross between a plant of genotype PpSs and the tester white plant with wrinkled seed coat (ppss) gives the following numbers of progeny in four phenotypic types. 14:87:83:16 (purple flower + smooth seed coat: purple flower + wrinkled seed coat: white flower + smooth seed coat: white flower + wrinkled seed coat).
a. What is the expected ratio of progeny phenotypes assuming independent assortment of alleles?
b. Explain how ratios of progeny show that the two genes are linked.
c. How many map units separate the purple and smooth genes? Show your calculations.
d. What is the “parental” genotype of the heterozygous parent? (i.e. Which alleles of the P and S loci are present on each of the two chromosomes of the doubly heterozygous parent of this test cross?)
The production of purple pigment in a certain species of flower is dependent upon two gene loci. You cross two purple flowered plants that are heterozygous at each gene locus. The offspring show the following phenotypes: 91 purple and 68 white.a. What is the simplified phenotypic ratio is observed in the offspring? What mode of inheritance is associated with this ratio?
b. What is/are the genotype(s) of the purple offspring? What is/are the genotype(s) of the white offspring?
Assume that plant height is determined by a pair of alleles at each of two loci (A and a, B and b) that are additive in their effects. Further assume that each allele represented by an uppercase letter contributes 6 feet to height and that each allele represented by a lowercase letter contributes 2 foot to height. If a plant with genotype Aabb is crossed to a plant with genotype aaBb, what heights are expected in the progeny?
1/216ft : 1/2 12ft
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1/4 20ft : 1/2 16ft : 1/4 12ft
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Chapter 3 Solutions
ND STONY BROOK UNIVERSITY LOOSELEAF GENETICS: FROM GENES TO GENOMES
Ch. 3 - For each of the terms in the left column, choose...Ch. 3 - In four-oclocks, the allele for red flowers is...Ch. 3 - The Aa heterozygous snapdragons in Fig. 3.3 are...Ch. 3 - Recall from Chapter 2 Fig. 2.20 that Mendels R...Ch. 3 - In the fruit fly Drosophila melanogaster, very...Ch. 3 - A cross between two plants that both have yellow...Ch. 3 - In radishes, color and shape are each controlled...Ch. 3 - A wild legume with white flowers and long pods is...Ch. 3 - Assuming no involvement of the Bombay phenotype in...Ch. 3 - Several genes in humans in addition to the ABO...
Ch. 3 - Alleles of the gene that determines seed coat...Ch. 3 - One of your fellow students tells you that there...Ch. 3 - In a population of rabbits, you find three...Ch. 3 - In clover plants, the pattern on the leaves is...Ch. 3 - Fruit flies with one allele for curly wings Cy and...Ch. 3 - In certain plant species such as tomatoes and...Ch. 3 - In a species of tropical fish, a colorful orange...Ch. 3 - People heterozygous for normal and nonfunctional...Ch. 3 - Using old Fugate family Bibles and the Perry...Ch. 3 - A rooster with a particular comb morphology called...Ch. 3 - A black mare was crossed to a chestnut stallion...Ch. 3 - Filled-in symbols in the pedigree that follows...Ch. 3 - You perform a cross between two true-breeding...Ch. 3 - a. How would you describe inheritance of flower...Ch. 3 - Suppose the intermediate called Colorless...Ch. 3 - Explain the difference between epistasis and...Ch. 3 - The dominant allele H reduces the number of body...Ch. 3 - Secretors genotypes SS and Ss secrete their A and...Ch. 3 - Normally, wild violets have yellow petals with...Ch. 3 - A woman who is blood type B has a child whose...Ch. 3 - The following table shows the responses of blood...Ch. 3 - Three different pure-breeding strains of corn that...Ch. 3 - In mice, the AY allele of the agouti gene is a...Ch. 3 - A student whose hobby was fishing pulled a very...Ch. 3 - Suppose that blue flower color in a plant species...Ch. 3 - This problem examines possible biochemical...Ch. 3 - Considering your answers to Problem 36, does the...Ch. 3 - You picked up two mice one female and one male...Ch. 3 - Figure 3.21 and Fig. 3.28b both show traits that...Ch. 3 - Three genes in fruit flies affect a particular...Ch. 3 - The garden flower Salpiglossis sinuata painted...Ch. 3 - In foxgloves, three different petal phenotypes...Ch. 3 - In a culture of fruit flies, matings between any...Ch. 3 - Prob. 44PCh. 3 - A couple wants to know the probability that their...Ch. 3 - This problem illustrates why classical geneticists...Ch. 3 - Prob. 47PCh. 3 - Familial hypercholesterolemia FH is an inherited...Ch. 3 - You have come into contact with two unrelated...Ch. 3 - Polycystic kidney disease is a dominant trait that...Ch. 3 - Identical monozygotic twins have similar, but not...Ch. 3 - Using each of the seven coat color genes discussed...
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