BRAINCAKEPopulation Bottlenecks and The Founder Effect
If in a particular generation, the size of a population suddenly and drastically reduces this is known as a population bottleneck and extreme form of genetic drift. This results in a reduction of genetic diversity. When the population recovers there will be fewer alleles in the gene pool. Examples are northern elephant seals which were hunted almost to extinction in the 19th century and cheetahs which experienced a bottleneck about 10,000 years ago.
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Key terms in this lesson
- allele
- One of two or more alternative versions of a gene, occupying the same locus on homologous chromosomes.
- gene pool
- All the alleles of all the genes present in a population at a given time.
- genetic drift
- Random changes in allele frequency in a population from generation to generation, having a greater effect in small populations.
More in Genetics and Variation
- Χ-squared Test
- Epistasis
- The Hardy-Weinberg Principle
- Changes in Allele Frequencies
- Types of Selection
- Species
- Allopatric Speciation
- Sympatric Speciation
All 36 lessons in Genetics and Variation · All AQA A-level Biology topics