Textbook Question
Identify and describe the evolutionary forces that can cause allele frequencies to change from one generation to the next.
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 D.4
Sanders 3rd EditionCh. 20 - Population Genetics and Evolution at the Population, Species, and Molecular LevelsProblem D.4Chapter 20, Problem D.4
Discuss how both gains and losses of regulatory elements may lead to human-specific traits.
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Begin by defining regulatory elements in genetics: these are DNA sequences such as enhancers, silencers, promoters, and insulators that control the expression of genes without altering the protein-coding sequence itself.
Explain that gains of regulatory elements refer to the acquisition of new regulatory sequences or the modification of existing ones, which can lead to novel patterns of gene expression unique to humans, potentially contributing to human-specific traits.
Discuss how losses of regulatory elements involve the deletion or inactivation of certain regulatory sequences, which can reduce or eliminate gene expression in specific contexts, also resulting in traits that distinguish humans from other species.
Illustrate with examples how changes in regulatory elements can affect developmental pathways, brain function, or other physiological processes, emphasizing that these changes can be subtle but have significant phenotypic effects.
Conclude by highlighting that both gains and losses of regulatory elements contribute to evolutionary divergence by altering gene expression patterns, thereby shaping human-specific traits without changing the underlying protein-coding genes.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Regulatory Elements in Genetics
Regulatory elements are DNA sequences such as enhancers, silencers, and promoters that control gene expression levels. They do not code for proteins but influence when, where, and how much a gene is expressed, playing a crucial role in development and phenotype.
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Human Transposable Elements
Gene Expression and Phenotypic Variation
Changes in gene expression, driven by regulatory elements, can lead to differences in traits without altering the underlying protein-coding genes. Variations in expression patterns contribute to phenotypic diversity, including species-specific characteristics.
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Evolutionary Impact of Gains and Losses of Regulatory Elements
Gains (e.g., new enhancers) or losses (e.g., deletion of silencers) of regulatory elements can modify gene expression patterns, leading to novel traits or loss of ancestral traits. Such changes are key mechanisms in human evolution, contributing to traits unique to our species.
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Related Practice
Textbook Question
What lines of evidence support the hypothesis that modern humans evolved in Africa and then subsequently migrated throughout the globe?
Textbook Question
Describe how natural selection can produce balanced polymorphism of allele frequencies through selection that favors heterozygotes.
Textbook Question
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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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.