Table of contents

1. Introduction to Genetics51m
2. Mendel's Laws of Inheritance3h 37m
3. Extensions to Mendelian Inheritance2h 41m
4. Genetic Mapping and Linkage2h 28m
5. Genetics of Bacteria and Viruses1h 21m
6. Chromosomal Variation1h 48m
7. DNA and Chromosome Structure56m
8. DNA Replication1h 10m
9. Mitosis and Meiosis1h 34m
10. Transcription1h 0m
11. Translation58m
12. Gene Regulation in Prokaryotes1h 19m
13. Gene Regulation in Eukaryotes44m
14. Genetic Control of Development44m
15. Genomes and Genomics1h 50m
16. Transposable Elements47m
17. Mutation, Repair, and Recombination1h 6m
18. Molecular Genetic Tools19m
- Genetic Cloning
  9m
- Methods for Analyzing DNA
  9m
19. Cancer Genetics29m
- Overview of Cancer
  21m
- Cancer Mutations
  7m
20. Quantitative Genetics1h 26m
21. Population Genetics50m
- Hardy Weinberg
  19m
- Allelic Frequency Changes
  31m
22. Evolutionary Genetics29m

21. Population Genetics

Allelic Frequency Changes

Genetics

21. Population Genetics

Allelic Frequency Changes

Previous problemNext problem

2:14 minutes

Problem 13a

Textbook Question

Two populations of deer, one of them large and living in a mainland forest and the other small and inhabiting a forest on an island, regularly exchange members that migrate across a land bridge that connects the island to the mainland. If you compared the allele frequencies in the two populations, what would you expect to find?

Verified step by step guidance

Understand the concept of gene flow: Gene flow refers to the transfer of alleles or genes from one population to another. In this case, migration across the land bridge facilitates gene flow between the mainland and island deer populations.

Consider the size of the populations: The mainland population is large, while the island population is small. This difference in population size affects the impact of gene flow. Allele frequencies in the smaller island population are more likely to be influenced by incoming migrants from the mainland.

Analyze the effect of migration: Migration tends to homogenize allele frequencies between populations. Over time, the allele frequencies in the island and mainland populations will become more similar due to the regular exchange of individuals.

Account for genetic drift: In the smaller island population, genetic drift (random changes in allele frequencies) may have a stronger effect compared to the larger mainland population. However, gene flow from the mainland can counteract these random changes, stabilizing allele frequencies.

Predict the outcome: Given regular migration, you would expect the allele frequencies in the two populations to converge over time, becoming more similar. However, the rate of convergence depends on the migration rate and the relative sizes of the populations.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Allele Frequency

Allele frequency refers to how often a particular allele appears in a population compared to other alleles for the same gene. It is a key measure in population genetics, indicating genetic diversity and the potential for evolution. Changes in allele frequencies over time can signal evolutionary processes such as natural selection, genetic drift, or gene flow.

Gene Flow

Gene flow is the transfer of genetic material between populations through migration and interbreeding. In the context of the deer populations, the exchange of members across the land bridge allows for gene flow, which can alter allele frequencies by introducing new alleles or changing the proportions of existing ones. This process can reduce genetic differences between populations and increase genetic diversity.

Population Structure

Population structure refers to the composition of a population in terms of genetic variation and how it is distributed among subpopulations. In this scenario, the mainland and island deer populations may exhibit different allele frequencies due to their distinct environments and sizes. However, regular migration can lead to homogenization of allele frequencies, making the populations more genetically similar over time.

Watch next

Master Natural Selection with a bite sized video explanation from Kylia

Start learning

Related Videos

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.

545

views

Textbook Question

If 4 percent of a population in equilibrium expresses a recessive trait, what is the probability that the offspring of two individuals who do not express the trait will express it?

479

views

Textbook Question

Under what circumstances might a lethal dominant allele persist in a population?

430

views

Textbook Question

Two populations of deer, one of them large and living in a mainland forest and the other small and inhabiting a forest on an island, regularly exchange members that migrate across a land bridge that connects the island to the mainland. An earthquake destroys the bridge between the island and the mainland, making migration impossible for the deer. What do you expect will happen to allele frequencies in the two populations over the following 10 generations?

Directional selection presents an apparent paradox. By favoring one allele and disfavoring others, directional selection can lead to fixation (a frequency of 1.0) of the favored allele, after which there is no genetic variation at the locus, and its evolution stops. Explain why directional selection no longer operates in populations after the favored allele reaches fixation.

386

views

Textbook Question

One of the first Mendelian traits identified in humans was a dominant condition known as brachydactyly. This gene causes an abnormal shortening of the fingers or toes (or both). At the time, some researchers thought that the dominant trait would spread until 75 percent of the population would be affected (because the phenotypic ratio of dominant to recessive is 3 : 1). Show that the reasoning was incorrect.

498

views

Textbook Question

What is inbreeding depression? Why is inbreeding depression a serious concern for animal biologists involved in species-conservation breeding programs?

724

views

Show more practices

Download the Mobile app

Privacy

Do not sell my personal information

Accessibility

Patent notice

Sitemap