Chapter 13 – Chromosomes, Mapping, and the Meiosis-Inheritance Connection
40. Given that these two gene loci are very closely linked, the phenotypic ratio in the F2
generation should be closest to
Chapter 13 – Chromosomes, Mapping, and the Meiosis-Inheritance Connection
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likely to produce the correct answer?
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•
Did your problem-solving process lead you to the correct answer? If not, where did the
process break down or lead you astray? How can you revise your approach to produce a
Chapter 13 – Chromosomes, Mapping, and the Meiosis-Inheritance Connection
more desirable result?
41. What would be the results of a test cross with the F1 flies?
Chapter 13 – Chromosomes, Mapping, and the Meiosis-Inheritance Connection
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at the phenotypes that result when crossed to a tester strain.
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alleles in the other parent are revealed in the progeny.
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•
Given what you now know, what information and/or problem solving approach is most
likely to produce the correct answer?
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•
Did your problem-solving process lead you to the correct answer? If not, where did the
process break down or lead you astray? How can you revise your approach to produce a
more desirable result?
Chapter 13 – Chromosomes, Mapping, and the Meiosis-Inheritance Connection
42. What is the relationship between recombination frequency and the actual
physical distance on a chromosome?
43. In a two-point cross to map genes A and B, you obtained 98 recombinant types and 902
parental types among the offspring. How far apart are these genes?
Chapter 13 – Chromosomes, Mapping, and the Meiosis-Inheritance Connection
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• What type of thinking is required?
• What key words does the question contain and what do they mean?
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• What do you already know about two-point mapping?
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• Given what you now know, what information and/or problem solving approach is most
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o Since 1 cM represents 1% recombination, we can say the distance is 9.8 cM.
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• Did your problem-solving process lead you to the correct answer? If not, where did the
process break down or lead you astray? How can you revise your approach to produce a
more desirable result?
Chapter 13 – Chromosomes, Mapping, and the Meiosis-Inheritance Connection
44. Morgan’s student Sturtevant demonstrated that the recombination frequencies between a
series of linked genes is additive. Examine the following recombination data from Sturtevant,
and determine the proper order of the genes on the Drosophila X chromosome. Assume y is in
the 0.0 position. Gene 1 Gene 2 Recombination frequency
yellow(y) vermilion(y) 0.322 vermilion miniature(m) 0.030
white(w) vermiliom 0.297 yellow white 0.010
white miniature 0.337
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o For this problem, drawing a diagram can be helpful.
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Chapter 13 – Chromosomes, Mapping, and the Meiosis-Inheritance Connection
likely to produce the correct answer?
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•
Did your problem-solving process lead you to the correct answer? If not, where did the
process break down or lead you astray? How can you revise your approach to produce a
more desirable result?
You are a forensic technician working on a DNA sample obtained from a crime scene. Your
job is to compare the unknown DNA sample with known DNA samples collected from five
different suspects. Preliminary analysis using only a few DNA markers revealed that the
unknown sample could possibly match two of the suspects. After consulting the case file, you
find out that these two suspects are brothers (but not twins). You realize that you will have to
do a more detailed analysis on the samples so that you can distinguish between the brothers
and determine which brothers’ DNA matches the unknown sample.
45. Which of the following will help you distinguish between the two final suspects?
Chapter 13 – Chromosomes, Mapping, and the Meiosis-Inheritance Connection
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•
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likely to produce the correct answer?
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•
Did your problem-solving process lead you to the correct answer? If not, where did the
process break down or lead you astray? How can you revise your approach to produce a
Chapter 13 – Chromosomes, Mapping, and the Meiosis-Inheritance Connection
more desirable result?
46. Why can’t you use mitochondrial DNA to distinguish between these two suspects?
Chapter 13 – Chromosomes, Mapping, and the Meiosis-Inheritance Connection
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process break down or lead you astray? How can you revise your approach to produce a
more desirable result?
Chapter 13 – Chromosomes, Mapping, and the Meiosis-Inheritance Connection
47. In some human populations, the proportion of individuals who are heterozygous for the
sickle cell allele is much higher than would be expected by chance alone. Why?
48. A deletion of a particular stretch of chromosome 15 can cause either Prader-Willi
syndrome or Angelman syndrome, depending on
Chapter 13 – Chromosomes, Mapping, and the Meiosis-Inheritance Connection
49. How did the development of anonymous markers aid in the production of a human
genetic map?
50. Why isn’t mitochondrial DNA a unique identifier?
Chapter 13 – Chromosomes, Mapping, and the Meiosis-Inheritance Connection
Fill in the Blank Questions
51. In humans, hemophilia is caused by a recessive allele on the X chromosome. Suppose a
man with hemophilia has children with a healthy woman whose mother had hemophilia. What
is the probability that their second child will have hemophilia? (Enter the probability as a
percent. Enter the number only without the percent sign. For example, enter 100% as 100 and
enter 12.5% as 12.5)
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Choose Answer
Chapter 13 – Chromosomes, Mapping, and the Meiosis-Inheritance Connection
•
Given what you now know, what information and/or problem solving approach is most
likely to produce the correct answer?
Reflect on Process
•
Did your problem-solving process lead you to the correct answer? If not, where did the
process break down or lead you astray? How can you revise your approach to produce a
more desirable result?
52. In humans, hemophilia is caused by a recessive allele on the X chromosome. Suppose a
man with hemophilia has children with a healthy woman whose mother had hemophilia. If an
ultrasound test shows that their first child is a girl, what is the probability that she has
hemophilia? (Enter the probability as a percent. Enter the number only without the percent
sign. For example, enter 100% as 100 and enter 12.5% as 12.5 )
Chapter 13 – Chromosomes, Mapping, and the Meiosis-Inheritance Connection
Clarify Question
•
What is the key concept addressed by the question?
•
What type of thinking is required?
•
What key words does the question contain?
Gather Content
•
What do you already know about X-linked inheritance?
Consider Possibilities
•
What other information is related to the question? Which information is most useful?
Choose Answer
•
Given what you now know, what information and/or problem solving approach is most
likely to produce the correct answer?
Reflect on Process
•
Did your problem-solving process lead you to the correct answer? If not, where did the
process break down or lead you astray? How can you revise your approach to produce a