Gene Flow and Genetic Drift

Gene flow and genetic drift are two processes among three different necessary processes required for the evolution of species. Both terms are different, however, they are interconnected too. Gene flow focuses on migrating the genes from one gene pool to another pool, while genetic drift depends on the allelic frequencies, an alternative form of genes. 

Definition of gene flow and genetic drift

• Gene flow can be defined as the transmission of genes or genetic material from gene pool on species to another gene pool by interbreeding and resulting in alteration of the recipient gene pool. Gene flow is also known as gene migration
• Genetic drift can be described as a strong effect of instability considering the allelic frequencies of small populations. It is generally caused due to random events, errors in allele selection, or sampling. Genetic drift occurs mainly in tiny populations because, in more significant populations, allelic frequencies mostly remain stable, freeing environmental factors like natural selection

Possible causes of gene flow and genetic drift

Gene flow and genetic drift are connected, but they differ in occurrence, size, variations, evolution, etc. The possible reasons of gene flow and sense on several aspects are mentioned below:

Reason of occurrence

Gene flow occurs through continuous interbreeding or cross-breeding between two nearby populations whereas genetic drift occurs by the sudden constant sampling errors, elimination, or imbalance in the allelic frequencies of a small group of genes.

Size of population

The acquisition of a process that genes undertake is highly dependent on the population of a species or group. The gene groups with smaller finite people tend to possess genetic drift. In contrast, the infinite populations or bigger groups perform gene flow, altering the recipient group’s gene pool.

Evolution

The evolution of new genotypes and traits occurs through gene flow and drift, and the only difference is how growth happens. In gene flow, a shift occurs with the immigration of genes to another species, composing their gene pool and causing variants in evolution. In genetic drift, the composition in adjacent populations is done through several effects: the bottleneck and the founder.

Genetic variations

The variations occur in gene flow primarily due to the size of their group. Many genetic transfers are seen due to gene flow because it occurs due to pure environmental immigration of molecules of gametes, which interbred with new populations, and the development of variations of allelic occur. This is the process through which alleles are formed. While in genetic drift, due to its sudden and short-term occurrence and small size, the evolution of variations might not take place.

Key difference: Gene flow and genetic drift

Factors affecting gene flow and genetic drift

Geographical obstructions

Geographical factors obstruct gene flow and genetic drift in some instances. On the other hand, some environmental conditions do not let them migrate necessarily and lead to divergence of genes or alleles, which leads to the prevention of processes. For example, some environmental factors lead to the geographical isolation of genes where they cannot interbreed with another population due to unavailability. Alternatively, human events like deforestation or forest fire also lead to the prevention of gene flow and genetic drift. 

Reproduction barriers

Reproduction barriers obstruct gene flow due to more miniature reproduction, or when a particular gene population is not favourable to reproduce, then it can cause prevention of gene flow. Moreover, in genetic drift, due to stoppage in the reproduction of alleles can increase the instability and prevent gene drift.

Examples of gene flow and genetic drift

Gene flow

Let us take the real-life example of Indian citizens in America to understand the gene flow. America might have had very few Indians residing in their state in the beginning. However, as time passed, Indians started migrating to America and settling there, increasing the number of Indians in America. After some time, several Indian colonies were established in America, which can be referenced as altering the gene pool.

Genetic drift

Let us take the example of children with tigers and brown eyes. The brown eye is found most compared to tiger-eyed children; this makes brown eyes a dominant allele. However, due to instability in tiger-eyed children, they might be endangered as their next generation might not remain with tiger eyes.

Conclusion

Above from here, we came through the Gene flow and genetic drift. We also learned their types, differences, functions, structures, and other minor aspects. This brief note about Gene flow and genetic drift can help you understand the concepts more quickly. That was all on the Gene flow and genetic drift. It has all topics covered in chemistry, biology, mathematics, economics, and many subjects you are interested in.