Textbook Question
How do we know that sister chromatids undergo recombination during mitosis?
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Ch. 7 - Linkage and Chromosome Mapping in Eukaryotes
Klug10th EditionEssentials of GeneticsISBN: 9780135588789
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Table of contents
- Ch. 1 - Introduction to Genetics16
- Ch. 2 - Mitosis and Meiosis28
- Ch. 3 - Mendelian Genetics37
- Ch. 4 - Modification of Mendelian Ratios53
- Ch. 5 - Sex Determination and Sex Chromosomes32
- Ch. 6 - Chromosome Mutations: Variation in Number and Arrangement37
- Ch. 7 - Linkage and Chromosome Mapping in Eukaryotes36
- Ch. 8 - Genetic Analysis and Mapping in Bacteria and Bacteriophages24
- Ch. 9 - DNA Structure and Analysis38
- Ch. 10 - DNA Replication29
- Ch. 11 - Chromosome Structure and DNA Sequence Organization22
- Ch. 12 - The Genetic Code and Transcription36
- Ch. 13 - Translation and Proteins27
- Ch. 14 - Gene Mutation, DNA Repair, and Transposition34
- Ch. 15 - Regulation of Gene Expression in Bacteria22
- Ch. 16 - Regulation of Gene Expression in Eukaryotes37
- Ch. 17 - Recombinant DNA Technology27
- Ch. 18 - Genomics, Bioinformatics, and Proteomics30
- Ch. 19 - The Genetics of Cancer21
- Ch. 20 - Quantitative Genetics and Multifactorial Traits37
- Ch. 21 - Population and Evolutionary Genetics45
Chapter 7, Problem 4
Why does more crossing over occur between two distantly linked genes than between two genes that are very close together on the same chromosome?
Verified step by step guidance1
Understand that crossing over occurs during meiosis when homologous chromosomes exchange segments, which increases genetic variation.
Recognize that the frequency of crossing over between two genes depends on the physical distance between them on the chromosome; the farther apart they are, the more likely a crossover event will occur between them.
Recall that genes that are very close together have less physical space between them, so the chance of a crossover happening between them is lower because the crossover event is a random process along the chromosome length.
Note that when genes are far apart, there is more chromosomal region where crossing over can occur, increasing the probability of at least one crossover event between those genes.
Conclude that the observed higher recombination frequency between distantly linked genes reflects the greater opportunity for crossover events due to their larger physical separation on the chromosome.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Genetic Linkage
Genetic linkage refers to the tendency of genes located close together on the same chromosome to be inherited together. Genes that are physically near each other have a lower chance of being separated by recombination during meiosis, resulting in fewer crossover events between them.
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Chi Square and Linkage
Crossing Over and Recombination
Crossing over is the process where homologous chromosomes exchange segments during meiosis, creating new allele combinations. The frequency of crossing over between two genes depends on the physical distance between them; greater distance increases the likelihood of recombination.
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Recombination Frequency as a Measure of Distance
Recombination frequency quantifies how often crossing over occurs between two genes and is used to estimate their distance on a chromosome. Genes far apart have higher recombination frequencies because there is more physical space for crossover events to happen between them.
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Related Practice
Textbook Question
Write a short essay that discusses how crossing over can be detected and how the resultant data provide the basis of chromosome mapping.
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Textbook Question
Describe the cytological observation that suggests that crossing over occurs during the first meiotic prophase.
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Textbook Question
Explain why a 50 percent recovery of single-crossover products is the upper limit, even when crossing over always occurs between two linked genes?
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Textbook Question
Why are double-crossover events expected less frequently than single-crossover events?
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Textbook Question
What is the proposed basis for positive interference?
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