Difference Between Gene Migration and Genetic Drift

The key difference between gene migration and genetic drift is that gene migration is the transfer of genes/alleles from one population to another population while genetic drift is the changes of alleles’ frequencies due to random sampling from one generation to another.

Gene migration and genetic drift are two terms commonly used in population genetics. Both terms are associated with the changes occurring in the genetic composition of a population.

CONTENTS

1. Overview and Key Difference
2. What is Gene Migration 
3. What is Genetic Drift
4. Similarities Between Gene Migration and Genetic Drift
5. Side by Side Comparison – Gene Migration vs Genetic Drift in Tabular Form
6. Summary

What is Gene Migration?

Gene migration, also known as gene flow, is the transfer of genetic material from one population to another. In simple words, gene migration is the movement of genes from one group of organisms to another group of organisms.

Changes in the gene composition of a population take place over time during gene flow. These changes are due to the gene movements rather than the mutations and natural selection. Therefore, the introduction or elimination of alleles is responsible for the changes in genetic makeup. Transfer of alleles in and out of gene pools takes place purely due to gene migration. It happens when organisms move into and out of a population.

What is Genetic Drift?

Genetic drift is a phenomenon which is much more likely to occur in small populations and more unlikely to occur in large populations. Basically, it occurs due to random changes in allele frequencies that could lead to the disappearance of some genes from small populations due to dying or not carrying out reproduction. Ultimately genetic drift causes less genetic diversity and variation in populations. Also, it causes the disappearance of some gene variants completely from the populations. Moreover, it can cause some rare alleles to become more frequent than before.

Genetic drift has two types as bottleneck effect and founder effect. They cause extreme reductions in populations. Bottleneck effect occurs when the population contracts significantly into a smaller size. It can occur due to natural disasters such as earthquakes, floods, fires. In contrast, the founder effect occurs when a small group in a population splinters off from the original population and forms a new one.

What are the Similarities Between Gene Migration and Genetic Drift?

• Gene flow and genetic drift are population genetics terms
• Due to both phenomena, the genetic makeup of an individual change.

What is the Difference Between Gene Migration and Genetic Drift?

Gene migration is the process of moving genes from one population to another while genetic drift is the changes in allele frequency in a population due to random sampling. So, this is the key difference between gene migration and genetic drift. Besides, the genetic variation takes place in gene migration, mainly due to the transfer of alleles into and out of gene pools. In contrast, in genetic drift, alteration of the allele frequencies of a population takes place due to due to random sampling.

Below infographic shows the difference between gene migration and genetic drift in tabular form.

Summary – Gene Migration vs Genetic Drift

Gene migration and genetic drift are two main phenomena that alter the genetic variation of a given population. Gene migration is the movement of genes from one population to another. When organisms move in and out of a population, gene migration takes place. In genetic drift, the allele frequency in a population changes across generations due to random effects. Genetic drift takes place mainly in small populations due to founder effect or bottleneck effect. Thus, this is the summary of the difference between gene migration and genetic drift.

Reference:

1. “Genetic Drift (Article) | Khan Academy”. Khan Academy, 2020, Available here.
2. “Gene Flow”. En.Wikipedia.Org, 2020, Available here.

Image Courtesy:

1. “Gene flow final” By Jessica Krueger – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Genetic drift in a population Figure 19 02 02” By OpenStax, Rice University – Textbook content produced by OpenStax, Rice University (CC BY 4.0) via Commons Wikimedia