Genetic_drift and gene flow Fall2024

Genetic Drift

Random changes in allele frequency due to sampling error, especially in small populations.

Sampling Error

Random deviations from expected results due to small sample sizes.

Fixation

When the frequency of an allele becomes 1 (100%) in a population.

Genetic Variation

The diversity in gene frequencies among individuals in a population.

Allele Frequency

The proportion of a specific allele among all allele copies in a population.

Founder Effect

The reduced genetic diversity that results when a small population establishes a new population.

Genetic Bottleneck

A sharp reduction in the size of a population due to environmental events or other pressures.

Heterozygosity

The presence of different alleles at one or more loci on chromosomes.

Vagility

The ability of an organism to move or disperse.

Gene Flow

The movement of alleles from one population to another.

Ecotype

Local populations adapted to specific environmental conditions.

Inbreeding

Mating between closely related individuals, often leading to reduced genetic diversity.

Migration (in genetics)

The movement of individuals into or out of a population, affecting allele frequencies.

Alleles

Different versions of a gene found at the same locus.

Cheetah Genetic Bottleneck

The low genetic variation in modern cheetah populations stemming from a historic bottleneck.

Genetic Rescue

The introduction of new genes into a population to increase genetic variation and reduce inbreeding effects.

Stochastic Processes

Random processes that can influence evolution, such as genetic drift.

Effective Population Size (Ne)

An estimate of the number of individuals in a population who contribute to the next generation.

Darwin's Finches

A group of bird species originating from a common ancestor, illustrating rapid adaptation.

Accelerated Fixation

The increased rate at which alleles become fixed in small populations compared to large ones.

Population Size Effect on Drift

Larger populations experience smaller effects from genetic drift.

Allele Loss

The disappearance of an allele from a population due to genetic drift.

Gene Flow Impact on Variability

Continued gene flow can reduce genetic differences between populations.

Microevolutionary Forces

Processes such as mutation, gene flow, genetic drift, and natural selection that drive evolutionary change.

Genetic Variation Decline Gradient

The decrease in genetic diversity observed with increasing distance from a population source.

Ellis van Creveld Syndrome

A rare genetic disorder that is more common among the Amish due to the founder effect.

Huntington’s Disease Frequency in Afrikaners

A higher incidence of the Huntington's disease allele among Afrikaners due to founder effect.

Pingelap Island Achromatopsia

A high frequency of a color vision deficiency following a historical bottleneck.

Barriers to Gene Flow

Geographical or ecological factors that impede the movement of alleles between populations.

Chicago Squirrels Case Study

An example describing how urban and rural adaptations can differ and be influenced by gene flow.

Genetic Diversity and Conservation

The importance of maintaining genetic variation for species survival and resilience.

Allelic Frequency Similarity in Humans

Human populations show a convergence of allele frequencies due to gene flow.

Genetic Variation and Evolutionary Success

The role of genetic diversity in adapting and surviving environmental changes.

Migration's Role in Population Genetics

How the exchange of individuals affects genetic structure and diversity within populations.