Chapter 4. Chapter 4: Completing a Four-Point Testcross

Introduction

Unpacking the Problem
true
true
You must read each slide, and complete any questions on the slide, in sequence.

An individual heterozygous for four genes, A/a·B/b·C/c·D/d, is testcrossed with a/a·b/b·c/c·d/d, and 1000 progeny are classified by the gamete contribution of the heterozygous parent as follows:

a·B·C·D 42
A·b·c·d 43
A·B·C·d 140
a·b·c·D 145
a·B·c·D 6
A·b·C·d 9
A·B·c·d 305
a·b·C·D 310

Which genes are linked? If two pure-breeding lines had been crossed to produce the heterozygous individual, what would their genotypes have been? Draw a linkage map of the linked genes, showing the order and the distances in map units. Calculate an interference value, if appropriate.

Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.

  • Part A (steps 1-3): Look carefully at the progeny data in the table. Look carefully at the specific genotypes and the number of each genotype among the 1000 progeny.
  • Part B (steps 4 and 5): Determine which genes are linked by understanding how the different progeny genotypes came to be and why pairs of genotypes appear in similar numbers among the progeny.
  • Part C (steps 6-9):Calculate recombination frequencies to determine map distances and the relative gene order.
  • Part D (steps 10 and 11): Calculate interference between adjacent crossovers.

Question

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
1

Introduction

Unpacking the Problem
true
true
You must read each slide, and complete any questions on the slide, in sequence.

An individual heterozygous for four genes, A/a·B/b·C/c·D/d, is testcrossed with a/a·b/b·c/c·d/d, and 1000 progeny are classified by the gamete contribution of the heterozygous parent as follows:

a·B·C·D 42
A·b·c·d 43
A·B·C·d 140
a·b·c·D 145
a·B·c·D 6
A·b·C·d 9
A·B·c·d 305
a·b·C·D 310

Which genes are linked? If two pure-breeding lines had been crossed to produce the heterozygous individual, what would their genotypes have been? Draw a linkage map of the linked genes, showing the order and the distances in map units. Calculate an interference value, if appropriate.

Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.

  • Part A (steps 1-3): Look carefully at the progeny data in the table. Look carefully at the specific genotypes and the number of each genotype among the 1000 progeny.
  • Part B (steps 4 and 5): Determine which genes are linked by understanding how the different progeny genotypes came to be and why pairs of genotypes appear in similar numbers among the progeny.
  • Part C (steps 6-9):Calculate recombination frequencies to determine map distances and the relative gene order.
  • Part D (steps 10 and 11): Calculate interference between adjacent crossovers.

Question

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
1

Introduction

Unpacking the Problem
true
true
You must read each slide, and complete any questions on the slide, in sequence.

An individual heterozygous for four genes, A/a·B/b·C/c·D/d, is testcrossed with a/a·b/b·c/c·d/d, and 1000 progeny are classified by the gamete contribution of the heterozygous parent as follows:

a·B·C·D 42
A·b·c·d 43
A·B·C·d 140
a·b·c·D 145
a·B·c·D 6
A·b·C·d 9
A·B·c·d 305
a·b·C·D 310

Which genes are linked? If two pure-breeding lines had been crossed to produce the heterozygous individual, what would their genotypes have been? Draw a linkage map of the linked genes, showing the order and the distances in map units. Calculate an interference value, if appropriate.

Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.

  • Part A (steps 1-3): Look carefully at the progeny data in the table. Look carefully at the specific genotypes and the number of each genotype among the 1000 progeny.
  • Part B (steps 4 and 5): Determine which genes are linked by understanding how the different progeny genotypes came to be and why pairs of genotypes appear in similar numbers among the progeny.
  • Part C (steps 6-9):Calculate recombination frequencies to determine map distances and the relative gene order.
  • Part D (steps 10 and 11): Calculate interference between adjacent crossovers.

Question

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
1

Introduction

Unpacking the Problem
true
true
You must read each slide, and complete any questions on the slide, in sequence.

An individual heterozygous for four genes, A/a·B/b·C/c·D/d, is testcrossed with a/a·b/b·c/c·d/d, and 1000 progeny are classified by the gamete contribution of the heterozygous parent as follows:

a·B·C·D 42
A·b·c·d 43
A·B·C·d 140
a·b·c·D 145
a·B·c·D 6
A·b·C·d 9
A·B·c·d 305
a·b·C·D 310

Which genes are linked? If two pure-breeding lines had been crossed to produce the heterozygous individual, what would their genotypes have been? Draw a linkage map of the linked genes, showing the order and the distances in map units. Calculate an interference value, if appropriate.

Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.

  • Part A (steps 1-3): Look carefully at the progeny data in the table. Look carefully at the specific genotypes and the number of each genotype among the 1000 progeny.
  • Part B (steps 4 and 5): Determine which genes are linked by understanding how the different progeny genotypes came to be and why pairs of genotypes appear in similar numbers among the progeny.
  • Part C (steps 6-9):Calculate recombination frequencies to determine map distances and the relative gene order.
  • Part D (steps 10 and 11): Calculate interference between adjacent crossovers.

Question

Describe a test that is diagnostic for linkage by filling in the blanks in the sentence below.
Analyze the sHFlcINYhK7qWh/I99TcLd1ZaRmqrlwsOb4chyKG9BQxHkDhVKqYhXtNho5Upscqz2Aga74lSKUtXU82MKyTgJEQvxra8m+A WenrrOZ+VkYHAWptrGamu7R6QNQ= at a time. They are linked when the MenuiEAhkF25HuU2fZmW8/pJel7H62dGaDXiV1A2XiGDT/EngmRGv/zNKpIyEPk4zm4CWH444ADZxFaQVL/jB6K1eLBURvkmO4KxF0TzbXg= is +6JGQ/B0/e1Th07WvMeZJk0OkwdhLlcYCcdhK93dnZeLCq0+ 7mg75SO7Mrc4PGuWeAzV4LxEWQ8OZjjqAfD3k53c7dCMeSoUjfifSnzuwXubECMLE+AXMA== .
Correct. When the progeny in a testcross reveal a recombinant frequency of less than 50%, then the pair of genes being analyzed must be linked.
Incorrect. Two genes that are close together on the same chromosome pair do not assort independently, so they produce a recombinant frequency of less than 50%. Thus, when the progeny in a testcross reveal a recombinant frequency of less than 50%, then the pair of genes being analyzed must be linked.
1

Introduction

Unpacking the Problem
true
true
You must read each slide, and complete any questions on the slide, in sequence.

An individual heterozygous for four genes, A/a·B/b·C/c·D/d, is testcrossed with a/a·b/b·c/c·d/d, and 1000 progeny are classified by the gamete contribution of the heterozygous parent as follows:

a·B·C·D 42
A·b·c·d 43
A·B·C·d 140
a·b·c·D 145
a·B·c·D 6
A·b·C·d 9
A·B·c·d 305
a·b·C·D 310

Which genes are linked? If two pure-breeding lines had been crossed to produce the heterozygous individual, what would their genotypes have been? Draw a linkage map of the linked genes, showing the order and the distances in map units. Calculate an interference value, if appropriate.

Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.

  • Part A (steps 1-3): Look carefully at the progeny data in the table. Look carefully at the specific genotypes and the number of each genotype among the 1000 progeny.
  • Part B (steps 4 and 5): Determine which genes are linked by understanding how the different progeny genotypes came to be and why pairs of genotypes appear in similar numbers among the progeny.
  • Part C (steps 6-9):Calculate recombination frequencies to determine map distances and the relative gene order.
  • Part D (steps 10 and 11): Calculate interference between adjacent crossovers.

Question

Which genes are linked? Fill in the table by choosing the correct answer from each pull-down menu.
A and B j4gwruJqTG7dPqKJ9BTmS0ADTE6+kpRogjXP8w==
A and C j4gwruJqTG7dPqKJ9BTmS0ADTE6+kpRogjXP8w==
A and D j4gwruJqTG7dPqKJ9BTmS0ADTE6+kpRogjXP8w==
B and C j4gwruJqTG7dPqKJ9BTmS0ADTE6+kpRogjXP8w==
B and D j4gwruJqTG7dPqKJ9BTmS0ADTE6+kpRogjXP8w==
C and D j4gwruJqTG7dPqKJ9BTmS0ADTE6+kpRogjXP8w==
1
Correct. Every pair of genes has a recombination frequency of less than 50%, so all of the genes are linked.
Incorrect. Every pair of genes has a recombination frequency of less than 50%, so all of the genes are linked. Review how you carried out the recombination frequency calculations.

Introduction

Unpacking the Problem
true
true
You must read each slide, and complete any questions on the slide, in sequence.

An individual heterozygous for four genes, A/a·B/b·C/c·D/d, is testcrossed with a/a·b/b·c/c·d/d, and 1000 progeny are classified by the gamete contribution of the heterozygous parent as follows:

a·B·C·D 42
A·b·c·d 43
A·B·C·d 140
a·b·c·D 145
a·B·c·D 6
A·b·C·d 9
A·B·c·d 305
a·b·C·D 310

Which genes are linked? If two pure-breeding lines had been crossed to produce the heterozygous individual, what would their genotypes have been? Draw a linkage map of the linked genes, showing the order and the distances in map units. Calculate an interference value, if appropriate.

Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.

  • Part A (steps 1-3): Look carefully at the progeny data in the table. Look carefully at the specific genotypes and the number of each genotype among the 1000 progeny.
  • Part B (steps 4 and 5): Determine which genes are linked by understanding how the different progeny genotypes came to be and why pairs of genotypes appear in similar numbers among the progeny.
  • Part C (steps 6-9):Calculate recombination frequencies to determine map distances and the relative gene order.
  • Part D (steps 10 and 11): Calculate interference between adjacent crossovers.

Question

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
1

Introduction

Unpacking the Problem
true
true
You must read each slide, and complete any questions on the slide, in sequence.

An individual heterozygous for four genes, A/a·B/b·C/c·D/d, is testcrossed with a/a·b/b·c/c·d/d, and 1000 progeny are classified by the gamete contribution of the heterozygous parent as follows:

a·B·C·D 42
A·b·c·d 43
A·B·C·d 140
a·b·c·D 145
a·B·c·D 6
A·b·C·d 9
A·B·c·d 305
a·b·C·D 310

Which genes are linked? If two pure-breeding lines had been crossed to produce the heterozygous individual, what would their genotypes have been? Draw a linkage map of the linked genes, showing the order and the distances in map units. Calculate an interference value, if appropriate.

Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.

  • Part A (steps 1-3): Look carefully at the progeny data in the table. Look carefully at the specific genotypes and the number of each genotype among the 1000 progeny.
  • Part B (steps 4 and 5): Determine which genes are linked by understanding how the different progeny genotypes came to be and why pairs of genotypes appear in similar numbers among the progeny.
  • Part C (steps 6-9):Calculate recombination frequencies to determine map distances and the relative gene order.
  • Part D (steps 10 and 11): Calculate interference between adjacent crossovers.

Question

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
1

Introduction

Unpacking the Problem
true
true
You must read each slide, and complete any questions on the slide, in sequence.

An individual heterozygous for four genes, A/a·B/b·C/c·D/d, is testcrossed with a/a·b/b·c/c·d/d, and 1000 progeny are classified by the gamete contribution of the heterozygous parent as follows:

a·B·C·D 42
A·b·c·d 43
A·B·C·d 140
a·b·c·D 145
a·B·c·D 6
A·b·C·d 9
A·B·c·d 305
a·b·C·D 310

Which genes are linked? If two pure-breeding lines had been crossed to produce the heterozygous individual, what would their genotypes have been? Draw a linkage map of the linked genes, showing the order and the distances in map units. Calculate an interference value, if appropriate.

Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.

  • Part A (steps 1-3): Look carefully at the progeny data in the table. Look carefully at the specific genotypes and the number of each genotype among the 1000 progeny.
  • Part B (steps 4 and 5): Determine which genes are linked by understanding how the different progeny genotypes came to be and why pairs of genotypes appear in similar numbers among the progeny.
  • Part C (steps 6-9):Calculate recombination frequencies to determine map distances and the relative gene order.
  • Part D (steps 10 and 11): Calculate interference between adjacent crossovers.

Question

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
1

Introduction

Unpacking the Problem
true
true
You must read each slide, and complete any questions on the slide, in sequence.

An individual heterozygous for four genes, A/a·B/b·C/c·D/d, is testcrossed with a/a·b/b·c/c·d/d, and 1000 progeny are classified by the gamete contribution of the heterozygous parent as follows:

a·B·C·D 42
A·b·c·d 43
A·B·C·d 140
a·b·c·D 145
a·B·c·D 6
A·b·C·d 9
A·B·c·d 305
a·b·C·D 310

Which genes are linked? If two pure-breeding lines had been crossed to produce the heterozygous individual, what would their genotypes have been? Draw a linkage map of the linked genes, showing the order and the distances in map units. Calculate an interference value, if appropriate.

Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.

  • Part A (steps 1-3): Look carefully at the progeny data in the table. Look carefully at the specific genotypes and the number of each genotype among the 1000 progeny.
  • Part B (steps 4 and 5): Determine which genes are linked by understanding how the different progeny genotypes came to be and why pairs of genotypes appear in similar numbers among the progeny.
  • Part C (steps 6-9):Calculate recombination frequencies to determine map distances and the relative gene order.
  • Part D (steps 10 and 11): Calculate interference between adjacent crossovers.

Question

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
1

Introduction

Unpacking the Problem
true
true
You must read each slide, and complete any questions on the slide, in sequence.

An individual heterozygous for four genes, A/a·B/b·C/c·D/d, is testcrossed with a/a·b/b·c/c·d/d, and 1000 progeny are classified by the gamete contribution of the heterozygous parent as follows:

a·B·C·D 42
A·b·c·d 43
A·B·C·d 140
a·b·c·D 145
a·B·c·D 6
A·b·C·d 9
A·B·c·d 305
a·b·C·D 310

Which genes are linked? If two pure-breeding lines had been crossed to produce the heterozygous individual, what would their genotypes have been? Draw a linkage map of the linked genes, showing the order and the distances in map units. Calculate an interference value, if appropriate.

Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.

  • Part A (steps 1-3): Look carefully at the progeny data in the table. Look carefully at the specific genotypes and the number of each genotype among the 1000 progeny.
  • Part B (steps 4 and 5): Determine which genes are linked by understanding how the different progeny genotypes came to be and why pairs of genotypes appear in similar numbers among the progeny.
  • Part C (steps 6-9):Calculate recombination frequencies to determine map distances and the relative gene order.
  • Part D (steps 10 and 11): Calculate interference between adjacent crossovers.

Question

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
1

Introduction

Unpacking the Problem
true
true
You must read each slide, and complete any questions on the slide, in sequence.

An individual heterozygous for four genes, A/a·B/b·C/c·D/d, is testcrossed with a/a·b/b·c/c·d/d, and 1000 progeny are classified by the gamete contribution of the heterozygous parent as follows:

a·B·C·D 42
A·b·c·d 43
A·B·C·d 140
a·b·c·D 145
a·B·c·D 6
A·b·C·d 9
A·B·c·d 305
a·b·C·D 310

Which genes are linked? If two pure-breeding lines had been crossed to produce the heterozygous individual, what would their genotypes have been? Draw a linkage map of the linked genes, showing the order and the distances in map units. Calculate an interference value, if appropriate.

Unpack the Problem: Break this problem into several parts and arrive at a solution using this guided, step-by-step approach.

  • Part A (steps 1-3): Look carefully at the progeny data in the table. Look carefully at the specific genotypes and the number of each genotype among the 1000 progeny.
  • Part B (steps 4 and 5): Determine which genes are linked by understanding how the different progeny genotypes came to be and why pairs of genotypes appear in similar numbers among the progeny.
  • Part C (steps 6-9):Calculate recombination frequencies to determine map distances and the relative gene order.
  • Part D (steps 10 and 11): Calculate interference between adjacent crossovers.

Question

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
1

Conclusion

This four-point testcross reduces to the familiar three-point testcross because genes A and D are so close together on the chromosome that they do not exhibit any crossing over and hence no recombination. A clue that this four-point testcross had an anomaly was the presence of only 8 gamete genotypes instead of the expected 16. The recombination frequencies can be calculated from the table provided of gamete genotypes found in the 1000 progeny. These values are then used to determine the gene order and the map distances between the genes. The most frequent gamete genotypes among the progeny are the parentals and reveal the alleles that are grouped together on each individual chromosome.