Related Experiment Video
Updated: May 22, 2026
10:17
An Allele-specific Gene Expression Assay to Test the Functional Basis of Genetic Associations
Published on: November 3, 2010
Allele Frequency Spectra as a General Tool for Modeling Genetic Diversity.
Ola Hössjer1, Linda Laikre2, Nils Ryman2
1Department of Mathematics, Stockholm University, SE 106 91, Stockholm, Sweden. ola@math.su.se.
Acta Biotheoretica
|May 20, 2026
Summary
This study develops a framework to analyze genetic variation and allele frequency spectrum (AFS) in populations with differing sizes. It models population bottlenecks and genetic drift to understand changes in genetic diversity over time.
Area of Science:
- Population Genetics
- Evolutionary Biology
- Quantitative Genetics
Background:
- Genetic variation is fundamental to evolution.
- Understanding allele frequency spectrum (AFS) is key to population genetics.
- Population size fluctuations, like bottlenecks, significantly impact genetic diversity.
Purpose of the Study:
- To develop a general framework for analyzing genetic variation at a polymorphic locus.
- To model the allele frequency spectrum (AFS) and its functionals in populations with varying census and effective sizes.
- To investigate the impact of rapid population bottlenecks on genetic diversity and equilibrium dynamics.
Main Methods:
- Developed exact recursions for the expected AFS and its functionals.
- Created a grid-based numerical algorithm for AFS calculations.
- Applied methods to populations experiencing bottlenecks and size changes, using exact and approximate calculations.
Main Results:
- Established a framework for studying genetic variation and AFS.
- Modeled the effects of population bottlenecks on genetic diversity.
- Provided computational tools for analyzing genetic diversity in dynamic populations.
Conclusions:
- The developed framework accurately models genetic variation dynamics.
- Population bottlenecks lead to significant shifts in AFS and genetic diversity.
- The numerical algorithm is effective for both small and large populations undergoing size changes.
Related Concept Videos
01:25What is Population Genetics?
A population is composed of members of the same species that simultaneously live and interact in the same area. When individuals in a population breed, they pass down their genes to their offspring. Many of these genes are polymorphic, meaning that they occur in multiple variants. Such variations of a gene are referred to as alleles. The collective set of all the alleles within a population is known as the gene pool.
01:49Hardy-Weinberg Principle
Diploid organisms have two alleles of each gene, one from each parent, in their somatic cells. Therefore, each individual contributes two alleles to the gene pool of the population. The gene pool of a population is the sum of every allele of all genes within that population and has some degree of variation. Genetic variation is typically expressed as a relative frequency, which is the percentage of the total population that has a given allele, genotype or phenotype.
01:09Mutation, Gene Flow, and Genetic Drift
In a population that is not at Hardy-Weinberg equilibrium, the frequency of alleles changes over time. Therefore, any deviations from the five conditions of Hardy-Weinberg equilibrium can alter the genetic variation of a given population. Conditions that change the genetic variability of a population include mutations, natural selection, non-random mating, gene flow, and genetic drift (small population size).
01:25Genetic Variation
Genetic variation is the diversity in DNA sequences found among individuals of the same species. This diversity is crucial for a species' survival because it helps organisms adapt to environmental changes. Genetic variation begins with fertilization, where an egg and sperm cell merge. Each of these cells carries 23 chromosomes, up to 46 in the fertilized egg. Chromosomes are long DNA strands that contain genes, the basic units of heredity.
Genes exist in different versions called alleles, which...
Genes exist in different versions called alleles, which...
03:33Genetic Drift
Natural selection—probably the most well-known evolutionary mechanism—increases the prevalence of traits that enhance survival and reproduction. However, evolution does not merely propagate favorable traits, nor does it always benefit populations.
02:54Evolutionary Relationships through Genome Comparisons
Genome comparison is one of the excellent ways to interpret the evolutionary relationships between organisms. The basic principle of genome comparison is that if two species share a common feature, it is likely encoded by the DNA sequence conserved between both species. The advent of genome sequencing technologies in the late 20th century enabled scientists to understand the concept of conservation of domains between species and helped them to deduce evolutionary relationships across diverse...