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- Title
Genetic signatures of occasional sex in parthenogenetic subpopulations of the freshwater planarian Schmidtea polychroa.
- Authors
D'Souza, Thomas C.; Michiels, Nico K.
- Abstract
1. Occasional sex in organisms that otherwise propagate clonally combines the advantages of both reproductive modes. Although theory predicts that this is a winning combination, evidence for its long-term importance in natural populations is scarce. 2. We studied the sperm-dependent parthenogenetic form of the freshwater planarian Schmidtea (formerly Dugesia) polychroa in which occasional sex is known to occur. By comparing subpopulations within the same lake, we showed that occasional sex does indeed leave telltale signatures in the population genetic structure of this species. 3. Using microsatellites, we found differences in genotypic diversity and evenness between six local subpopulations. Moreover, some locations showed temporal fluctuations in genotype and/or allele frequencies, while stability was observed in others. The results indicate that although some subpopulations show all the traits of clonal reproduction, others clearly have characteristics typical of sexual recombination, including the particular subpopulation for which we previously demonstrated the occurrence of occasional sex. 4. We show that within the same metapopulation, neighbouring localities can differ in the degree of occasional sex, as demonstrated by genetic signatures of clonality versus (occasional) genetic recombination. This makes S. polychroa particularly suitable to test the role of occasional sex to explain the persistence of parthenogenesis.
- Subjects
PARTHENOGENESIS; GENETIC recombination; GENETIC polymorphisms; REPRODUCTION; AQUATIC ecology; SPERMATOZOA; LAKES; FRESHWATER organisms; GYNOGENESIS
- Publication
Freshwater Biology, 2006, Vol 51, Issue 10, p1890
- ISSN
0046-5070
- Publication type
Article
- DOI
10.1111/j.1365-2427.2006.01622.x