The founder effect in population genetics refers to the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. The founder effect plays a crucial role in shaping genetic diversity within populations, and it can lead to unique evolutionary trajectories for isolated groups. Here are some key points about the founder effect:
- Origin and Definition:
- The founder effect was first fully outlined by biologist Ernst Mayr in 1942, building upon existing theoretical work by scientists like Sewall Wright.
- It occurs when a small group of migrants, who are not genetically representative of the parent population, establish themselves in a new area.
- As a result of this genetic bottleneck, the new population may exhibit distinct genotypic and phenotypic characteristics compared to the original population.
- Causes:
- The founder effect can arise due to migration, colonization, or isolation of a small group from the larger population.
- It can also occur during a population bottleneck, where a sudden reduction in population size leads to a limited gene pool.
- Consequences:
- Reduced genetic variation: The small founding population carries only a subset of the genetic diversity present in the larger population.
- Increased sensitivity to genetic drift: With fewer individuals, random fluctuations in allele frequencies can have a significant impact.
- Higher inbreeding: Mating among close relatives becomes more likely.
- Lower genetic diversity: The new population may lack the full range of genetic variants seen in the parent population.
- Founder Mutation:
- A specific type of founder effect is the founder mutation.
- It involves a mutation that appears in the DNA of one or more individuals who become founders of a distinct population.
- Over generations, the proportion of the mutated haplotype shared by carriers decreases due to genetic recombination, allowing scientists to estimate the mutation’s age[1].
References
- ↑ Founder effect - Wikipedia