Bottleneck Effect

Definition

The bottleneck effect is another form of genetic drift where an event drastically reduces the size of a population and consequently its genetic variation.

Analogy

Think about pouring ketchup out of a bottle - not all the ketchup can get through the narrow neck at once. Similarly, during an extreme event like a natural disaster, not all members (and thus not all genes) make it through 'the bottleneck', resulting in reduced genetic diversity.

Related terms

Genetic Variation: Differences among individuals in their DNA sequence.

Survival of the Fittest: A concept that describes how only those organisms best adapted to their environment tend to survive and transmit their genetic characteristics to succeeding generations.

Natural Selection: The process whereby organisms better adapted to their environment tend to survive and produce more offspring.