| Abstract: | Colonization dynamics may strongly influence within and among population genetic variation and evolutionary potential of populations. We here analyze the genetic structure during the first three years of 12 cyclical parthenogenetic Daphnia populations in newly created pond habitats. One to three genotypes were observed to colonize the populations, indicating a limited number of founders. Pronounced changes in genetic structure were associated with hatching of sexual dormant eggs after a period of absence of the newly founded populations from the active community. Despite rapid colonization, genetic differentiation among populations was fairly high with limited decay over time, suggesting long-lasting founder effects. After initial colonization, no new alleles were observed in any of the populations, and our analyses suggests that this reflects reduced establishment success of later arrivals. Rare alleles increased in frequency, which likely is the result of inbreeding depression in selfed offspring of initially abundant clones, providing a fitness advantage to the sexual offspring of initially rare clones. |
