Pullonkaulailmiöt

Pullonkaulailmiö, also known as the bottleneck effect, is a phenomenon in evolutionary biology. It occurs when a population's size is severely reduced for a short period of time. This reduction can be caused by various events such as natural disasters, disease, or human activities.

During a bottleneck event, the genetic diversity of the population is significantly reduced. Only a small fraction of the original gene pool survives. The surviving individuals then reproduce, and the new population will have a genetic makeup that reflects the limited gene pool of the survivors. This can lead to a loss of beneficial alleles and an increase in the frequency of deleterious alleles.

Populations that have experienced a bottleneck are often more vulnerable to future environmental changes or diseases because of their reduced genetic variation. This can make them less adaptable. Examples of species that have gone through bottleneck events include the northern elephant seal and the cheetah. These species exhibit very low genetic diversity, which is thought to be a consequence of past population reductions. Understanding bottleneck effects is crucial for conservation efforts, as it highlights the importance of maintaining genetic diversity within populations to ensure their long-term survival and adaptability.