How does genetic drift contribute to evolution?
Genetic drift is a process in which allele frequencies within a population change by chance alone as a result of sampling error from generation to generation. Genetic drift is a random process that can lead to large changes in populations over a short period of time.
In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. It was first fully outlined by Ernst Mayr in 1942, using existing theoretical work by those such as Sewall Wright.
- History of the concept. The concept of genetic drift was first introduced by one of the founders in the field of population genetics, Sewall Wright. His first use of the term "drift" was in 1929, though at the time he was using it in the sense of a directed process of change, or natural selection.
- Both bottlenecks and founder effects provide perfect opportunities for genetic drift to take over, as they both involve small populations. After a few generations, the population may look very different from the original population. In rare cases, a bottleneck may even lead to speciation.
- Gene flow or migration between two populations will help maintain similarities between the species, thus preventing (or slowing down) the process of speciation. In other words, gene flow/migration can help maintain genetic diversity in a population, but it will decrease variation between two populations.
Population bottleneck, when a population's size becomes very small very quickly, and the founder effect, when a few individuals in a population colonize a new location that is separate from the old population, are the two main types of genetic drift.
- Bottlenecks and founder effects. Genetic drift can cause big losses of genetic variation for small populations. Population bottlenecks occur when a population's size is reduced for at least one generation.
- Genetic drift is the changes in allele frequency in a gene pool. The bottleneck effect and founder effect are prime examples of genetic drift. Genetic drift is the changes in allele frequency in a population. Gene flow is the proccess of alleles moving from one population to another.
- Natural selection and genetic drift both result in a change in the frequency of alleles in a population, so both are mechanisms of evolution. However, the two processes differ in how they cause allele frequencies to change.
Founder effect refers to the loss of genetic variation when a new colony is established by a very small number of individuals away from a larger population. Population bottlenecks increase genetic drift. They also increase inbreeding due to the reduced pool of possible mates.
- The Founder Effect is defined as a type of bottleneck, "a type of genetic drift describing the loss of the allelic variation that accompanies founding of a new population from a very small number of individuals (a small sample of a much larger source population).
- Genetic drift describes random fluctuations in the numbers of gene variants in a population. Genetic drift takes place when the occurrence of variant forms of a gene, called alleles, increases and decreases by chance over time. These variations in the presence of alleles are measured as changes in allele frequencies.
- The Hardy–Weinberg principle, also known as the Hardy–Weinberg equilibrium, model, theorem, or law, states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences.
Updated: 6th October 2019