Definition of gene flow and genetic drift

Genetic variety is most likely ensured by genetic flow since alleles change when organisms migrate to another community. Genetic drift, on the other hand, is less likely to assure allele variation since it is more dependent on chance.

GENE FLOW: Gene flow, also known as gene migration, is the transfer of genetic material from one population of organisms to another by interbreeding, altering the content of the recipient population’s gene pool. The entry of novel alleles via gene flow enhances population diversity and allows for new trait varieties. The majority of human gene flow occurs as a result of voluntary or forced movement of human groups.

In the context of demographic change, the bigger the gap in allele frequencies between resident and migrant individuals, as well as the larger the number of migrants, the greater the impact of migrants on the resident population’s genetic makeup.

The pace of gene flow across populations is influenced by a variety of factors. Gene flow is likely to be reduced in species with poor dispersion or mobility, as well as species that live in fragmented environments, have large distances between populations, and have small population numbers. The pace of dispersal is influenced by mobility, since more mobile individuals have more opportunities to relocate.

CAUSE OF GENE FLOW: Migration and subsequent interbreeding with new populations, as well as gametes movement driven by pollination, produce gene flow. The goal of human-assisted gene flow is to boost the population size of vulnerable species.

EFFECT OF GENE FLOW: Gene flow has the function of reducing genetic differences across populations, preventing or delaying the development of populations in various geographical locations into distinct disease species.

GENETIC DRIFT: While certain gene variations (also known as alleles) can be selected for their ability to help or hinder an organism, others may have no effect. Genetic drift occurs when the frequency of an allele in a population fluctuates owing to reasons other than the allele itself. Several temporal trajectories for the same genes are depicted in the graph below. As you can see, the frequency of these genes varies a lot over time, especially in small populations.

The allele frequency of each gene is generally steady in the biggest populations. This occurs because the genes have no effect on fitness, hence there is no natural selection pressure for or against the allele. The frequency of these genes can vary dramatically in even the tiniest populations. Some people get ingrained in the population, while others vanish. Genetic drift refers to the random occurrences that contribute to fluctuations in frequency.

TYPE OF GENETIC DRIFT

Population Bottleneck: A population bottleneck is a kind of genetic drift in which the size of a population shrinks dramatically. These enormous population reductions are caused by competition, sickness, or predation. The organisms that did not perish now decide the allele pool. Because they are the only alleles remaining, certain alleles rise in frequency. When patients don’t finish their antibiotic treatment, this form of genetic drift occurs.

Founder Effect: A new population is produced, or “founded,” in a new area due to another sort of genetic drift known as the founder effect. If this new group does not interact and reproduce with the parent population, the allele frequencies will be very different. Because of the founder effect, many islands have species that exclusively live on that island. If only two birds of a species land on an island, for example, the variety there will be accounted for solely by their alleles.

While these alleles will initially predominate, mutations will occur in the population, resulting in new adaptations. The founding population retains this new adaptability. The two populations can diverge to the point that they can no longer interbreed if given enough time. This is a common mechanism for species to split off.

CAUSE OF GENETIC DRIFT: Smaller populations are more prone to genetic drift. Any of the alleles can become extinct in a small population with multiple alleles. There is less likelihood of losing a whole allele in a population with numerous creatures. This is due to the fact that alleles are found in numerous species, and they cannot all be eliminated. The allele frequency rises if the allele influences the organism in such a way that it induces more DNA reproduction. If an allele causes harm to the organism, its frequency declines. Genetic drift occurs when the frequency of an allele grows or drops as a result of its existence in a random creature that survives.

EFFECT OF GENETIC DRIFT: Genetic leads in a loss of variety in the genetic pool, where the frequency of specific genes may be fixed at the same level as it was in the population from the start. Another effect of genetic drifting is an increase in population differentiation, where different populations of the same species may have different alleles as a result of genetic drifting. This occurs when the frequency of one allele is fixed in one population but decreases in another population as the frequencies of alleles in the genetic pool move in opposite directions.

Small populations can experience higher fluctuations in allele frequencies due to sampling error than large populations. Because the gene pool of big populations tends to be more stable, alleles in small populations are fixed more quickly than in large populations. Large populations, on the other hand, are affected by genetic drift when they become small as a result of a natural disaster that drastically reduces population size until conditions improve and allow the population to grow again (bottleneck effect) or when a small population leaves the group to start a new colony when the population is threatened (founder effect). To keep a small population from going extinct, genetic diversity must be preserved. As a result, genetic drift must be reduced, and mutation must be preserved to allow for adaptability.

CONCLUSION

Genetic variety is most likely ensured by genetic flow since alleles change when organisms migrate to another community.  On the other hand, genetic drift less likely ensures allele variation as it is more dependent on chance.