Gene Flow

Introduction

Gene flow is the transfer of genes in a population. Gene flow is an important phenomenon that can contribute to the Evolution of a Population. All organisms are subject to this phenomenon, which has a profound evolutionary impact. Depending on the rates of gene flow, the process either encourages genetic diversity among populations or leads to genetic homogeneity.

Gene Flow

Gene flow is the exchange of genes between two different populations. It is also referred to as gene migration. This exchange of genes between populations occurs when people migrate or gametes are dispersed. Gene flow happens whenever a gene is added into a population where it did not previously exist. This is most typically accomplished when animals or plant spores migrate to a new place. For instance, the seeds of many plants are dispersed by the wind or carried by animals' digestive tracts. These seeds could introduce rare alleles from the parent population to the new population.

Consider this example for Gene Flow

In essence, all dogs were wolves 15,000 years ago. All aspects of a dog's look have almost entirely changed. Dogs are now used in a variety of ways, compared to the past when they were much more driven to hunt. Large sheepdog breeds were developed with a protective attitude in mind as some people wanted dogs to guard their flocks. The dachshund's job was to hunt mice and rabbits in confined areas. The golden retriever was created to meet the need for a fluffy-haired, fetch-loving dog. The populations of dogs got more unique as these breeders paid closer attention to their desired qualities. Despite this, they are all associated with the same species.

In this regard, gene flow is similar to a Labradoodle or the Puggle, a mix between a pug and a beagle. Due to the introduction of new genes, one dog from a purebred population can interbreed. As more variations are discovered, gene diversity grows. So the Labradoodle has Poodle hair but Labrador brains.

What are Genes?

Genes are the fundamental structural and functional unit of heredity. Genes are composed of DNA sequences, or genotypes, and changes to DNA will have an impact on natural selection and evolution. Genetics and other variables have a role in determining an organism's phenotypic characteristics, such as how the environment affects it.

Gene flow

Gene flow is the term used in population genetics to describe the movement of genes or alleles between interbreeding populations of a species. The allele frequencies of the offspring may change when individuals from different gene pools mate. Therefore, the genetic diversity within a population may be influenced by the gene pool.

For instance, if people from a population of a certain species move to a new place and marry individuals among the population already existing there, the result could be gene flow. Therefore, highly mobile species are more prone to experience allele frequency shifts brought on by gene flow.

Process of Gene Flow

Gene flow increases population diversity and enables new characteristic combinations by introducing unique alleles. The process begins with the interbreeding of genetic material from one population of a species to another, changing the gene pool of the recipient population in the process. Humans experience gene flow mostly as a result of forced or voluntary mobility of human groups. In the case of migration, the impact of migrants on the genetic makeup of the resident population increases with both the size of the allele frequency gap between residents and migrants and with the number of migrants.

How Does the Rate of Gene Flow Affect Genetic Diversity?

The introduction of Novel Alleles into a population creates genetic diversity when the rate of gene flow is modest. On the other side, a high rate of gene flow increases homogeneity by lowering genetic diversity among groups.

Impact of Gene Flow

The spread of genes from one group to another is the primary cause of evolution. When there is migration, gene flow happens. Even in the absence of any other active evolutionary forces, the loss or addition of individuals can quickly alter the gene pool frequencies.

For instance, if all Norwegians with red hair left the country, the subsequent generation would likely contain just a small number of people with this trait. The demographics to where the red-haired people migrated would also change over time.

Factors Affecting Gene Flow

Gene flow is affected by a variety of factors. Mobility, Geographical barriers, geological events, and physical obstacles are all factors that affect the rate of gene flow.

• Mobility − Mobility has a big impact on how quickly genes move between groups. More mobile species are more likely to contribute to gene flow through migration. Since pollen and seeds can travel great distances due to the wind and other animals, plants, which are stationary species, can encourage gene flow. Migration does not, however, guarantee gene flow on its own; there must also be a genetic exchange between the migratory population and the local population.

• Physical Barriers − Barriers in the reproductive and structural systems can limit gene flow. For instance, allopatric speciation occurs when geographical barriers separate populations of the same species and prevent gene flow.

  When a species becomes isolated due to physical features like mountain ranges, rivers, or structures, as well as social changes like emigration, this process is known as allopatric speciation.

• Geographical Barriers − A geographical barrier might be a road that separates the populations of blossoming plant species on each side. If the pollen from one plant can fertilize the other and produce live offspring, the gene pools of this species may recombine. On the other hand, if this barrier prevents the plant from getting to the population of plants of the same species on the other side, gene flow between the two populations may be restricted.

• Physical Barriers − Physical barriers to gene flow prohibit populations of the same species from exchanging genetic information, which leads to geographic isolation. Deserts, mountain ranges, and impassable oceans are a few examples. In certain instances, man-made barriers like the Great Wall of China have restricted the exchange of genetic material across populations of wild plants.

Siberian elm, also known as Chinese elm, is one of these native species and demonstrates less genetic diversity than plants like jujube and Armenian plum that grow on the other side of the Great Wall of China. This is so because Siberian elm, which needs wind pollination to reproduce, can out compete plants that need insect pollination.

Conclusion

In this tutorial, we learned what gene and gene flow are, how they work, and what influences them. Although gene flow does not affect the allele frequencies of a species as a whole, it can modify the allele frequencies of local populations.

FAQs

Qns 1. What happens if there is no gene flow?

Ans If there is no gene flow between two populations and they become isolated from one another, they may separate into two different species. This process is referred to as "speciation."

Qns 2. Is gene flow possible without migration?

Ans Gene flow is possible without migration. Consider this, the genes of one population will be transferred to another when a traveller returns home after successfully mating with members of the population in another region.