Textbook Question
Describe how selection at a locus can result in a loss of polymorphism surrounding the locus.
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.10
Sanders 3rd EditionCh. 20 - Population Genetics and Evolution at the Population, Species, and Molecular LevelsProblem D.10Chapter 20, Problem D.10
Denisovans are known from bones found in Denisova Cave in the Altai Mountains in Siberia, but traces of their DNA are found in Australians and Melanesians, whose ancestors likely migrated across Asia much farther to the south. How can these geographic differences be reconciled?
Verified step by step guidance1
Step 1: Understand the context of Denisovans as an archaic human group identified primarily from fossils found in Denisova Cave in Siberia, but whose genetic legacy appears in modern populations far from that location, such as Australians and Melanesians.
Step 2: Recognize that the presence of Denisovan DNA in distant populations suggests historical interbreeding events between Denisovans and the ancestors of these modern groups during their migration.
Step 3: Consider the migration routes of early modern humans out of Africa, which likely passed through Asia and could have overlapped geographically and temporally with Denisovan populations, allowing for gene flow.
Step 4: Explore the concept of gene flow and admixture, where interbreeding between distinct populations results in the transfer of genetic material, explaining how Denisovan DNA could be present in populations far from the original fossil site.
Step 5: Synthesize this information to conclude that the geographic differences can be reconciled by understanding that Denisovans had a wider range than the fossil record alone shows, and that their genetic influence spread through admixture with migrating modern humans across Asia.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Ancient Human Migration
Ancient human migration refers to the movement of early human populations across different regions over time. Understanding migration routes helps explain how genetic material from groups like Denisovans spread far from their original locations, such as from Siberia to Southeast Asia and Oceania.
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Human Genome Composition
Interbreeding and Genetic Admixture
Interbreeding between distinct hominin groups, such as Denisovans and modern humans, led to genetic admixture. This process results in the presence of Denisovan DNA in modern populations, even if those populations live far from where Denisovan fossils were found.
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Population Genetics and DNA Tracing
Population genetics studies the distribution of genetic variations within and between populations. By analyzing DNA sequences, scientists can trace ancestral relationships and migration patterns, revealing how Denisovan genetic markers appear in distant populations like Australians and Melanesians.
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Related Practice
Textbook Question
George Udny Yule was wrong in suggesting that an autosomal dominant trait like brachydactyly will increase in frequency in populations. Explain why Yule was incorrect.
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Textbook Question
How can ancient DNA provide insight into past migrations that analyses of extant human genomes fail to uncover?
Textbook Question
The ability to taste the bitter compound phenylthiocarbamide (PTC) is an autosomal dominant trait. The inability to taste PTC is a recessive condition. In a sample of 500 people, 360 have the ability to taste PTC and 140 do not. Calculate the frequency of the recessive allele.
Textbook Question
The ability to taste the bitter compound phenylthiocarbamide (PTC) is an autosomal dominant trait. The inability to taste PTC is a recessive condition. In a sample of 500 people, 360 have the ability to taste PTC and 140 do not. Calculate the frequency of the dominant allele.
Textbook Question
The ability to taste the bitter compound phenylthiocarbamide (PTC) is an autosomal dominant trait. The inability to taste PTC is a recessive condition. In a sample of 500 people, 360 have the ability to taste PTC and 140 do not. Calculate the frequency of each genotype.