What role does the bottleneck effect play in genetic diversity?

The bottleneck effect is a significant concept in genetics and evolutionary biology that describes how a dramatic reduction in population size can lead to a loss of genetic diversity. This event often occurs due to environmental disasters, habitat loss, or other drastic changes that drastically decrease the population. When the population size shrinks, the remaining individuals may not represent the genetic variation present in the original population. As a result, alleles that were once common can become rare or completely lost, leading to a decreased gene pool.

In small populations that emerge after a bottleneck, genetic diversity is limited because there are fewer individuals contributing to the next generation, which means there is less variation in the gene pool. This reduced genetic diversity can make populations more vulnerable to disease, environmental changes, and other factors that could affect their survival and adaptability. Therefore, the role of the bottleneck effect is characterized by its tendency to diminish genetic diversity within small populations, which can have long-term implications for the population's evolutionary trajectory and resilience.