Textbook Question
What lines of evidence support the hypothesis that modern humans evolved in Africa and then subsequently migrated throughout the globe?
Ch. 20 - Population Genetics and Evolution at the Population, Species, and Molecular Levels
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172
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Table of contents
- Ch. 1 - The Molecular Basis of Heredity, Variation, and Evolution64
- Ch. 2 - Transmission Genetics144
- Ch. 3 - Cell Division and Chromosome Heredity81
- Ch. 4 - Gene Interaction87
- Ch. 5 - Genetic Linkage and Mapping in Eukaryotes103
- Ch. 6 - Genetic Analysis and Mapping in Bacteria and Bacteriophages73
- Ch. 7 - DNA Structure and Replication71
- Ch. 8 - Molecular Biology of Transcription and RNA Processing79
- Ch. 9 - The Molecular Biology of Translation110
- Ch. 10 - Eukaryotic Chromosome Abnormalities and Molecular Organization100
- Ch. 11 - Gene Mutation, DNA Repair, and Homologous Recombination86
- Ch. 12 - Regulation of Gene Expression in Bacteria and Bacteriophage90
- Ch. 13 - Regulation of Gene Expression in Eukaryotes38
- Ch. 14 - Analysis of Gene Function via Forward Genetics and Reverse Genetics72
- Ch. 15 - Recombinant DNA Technology and Its Applications69
- Ch. 16 - Genomics: Genetics from a Whole-Genome Perspective49
- Ch. 17 - Organelle Inheritance and the Evolution of Organelle Genomes27
- Ch. 18 - Developmental Genetics43
- Ch. 19 - Genetic Analysis of Quantitative Traits66
- Ch. 20 - Population Genetics and Evolution at the Population, Species, and Molecular Levels105
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172Not the one you use?Change textbook
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Sanders 3rd EditionCh. 20 - Population Genetics and Evolution at the Population, Species, and Molecular LevelsProblem 5
Sanders 3rd EditionCh. 20 - Population Genetics and Evolution at the Population, Species, and Molecular LevelsProblem 5Chapter 20, Problem 5
Thinking creatively about evolutionary mechanisms, identify at least two schemes that could generate allelic polymorphism in a population. Do not include the processes described in the answer to Problem 4.
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Step 1: Understand the concept of allelic polymorphism, which refers to the presence of two or more alleles at a locus within a population, contributing to genetic diversity.
Step 2: Recall that evolutionary mechanisms generating allelic polymorphism include mutation, natural selection, gene flow, genetic drift, and recombination, but exclude those mentioned in Problem 4 as per the instructions.
Step 3: Consider mutation as one scheme: random changes in DNA sequences introduce new alleles into the population, increasing allelic variation over time.
Step 4: Consider balancing selection as another scheme: this includes mechanisms like heterozygote advantage or frequency-dependent selection, which maintain multiple alleles in the population by favoring genetic diversity.
Step 5: Summarize that both mutation (introducing new alleles) and balancing selection (maintaining multiple alleles) are key evolutionary schemes that can generate and sustain allelic polymorphism in populations.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Allelic Polymorphism
Allelic polymorphism refers to the presence of two or more different alleles at a gene locus within a population. This genetic variation is essential for evolution and adaptation, as it provides the raw material for natural selection to act upon.
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New Alleles and Migration
Balancing Selection
Balancing selection is an evolutionary mechanism that maintains multiple alleles in a population by providing a selective advantage to heterozygotes or through frequency-dependent selection. This process helps preserve genetic diversity and can generate stable allelic polymorphism.
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Mutation and Gene Flow
Mutation introduces new alleles into a population by altering DNA sequences, while gene flow involves the transfer of alleles between populations through migration. Both mechanisms increase genetic variation and can contribute to the generation and maintenance of allelic polymorphism.
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Related Practice
Textbook Question
Describe how natural selection can produce balanced polymorphism of allele frequencies through selection that favors heterozygotes.
Textbook Question
Discuss how both gains and losses of regulatory elements may lead to human-specific traits.
Textbook Question
How do copy-number variants arise? Do they account for more polymorphism than SNPs within the human population?
Textbook Question
Genetic drift, an evolutionary process affecting all populations, can have a significant effect in small populations, even though its effect is negligible in large populations. Explain why this is the case.
Textbook Question
Consider possible societal and ethical dilemmas that might arise if we currently shared the planet with another hominin.
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