title: Sex change and effective population size: implications for population genetic studies in marine fish.
abstract: Large variance in reproductive success is the primary factor that reduces effective population size (Ne) in natural populations. In sequentially hermaphroditic (sex-changing) fish, the sex ratio is typically skewed and biased towards the 'first' sex, while reproductive success increases considerably after sex change. Therefore, sex-changing fish populations are theoretically expected to have lower Ne than gonochorists (separate sexes), assuming all other parameters are essentially equal. In this study, we estimate Ne from genetic data collected from two ecologically similar species living along the eastern coast of South Africa: one gonochoristic, the 'santer' sea bream Cheimerius nufar, and one protogynous (female-first) sex changer, the 'slinger' sea bream Chrysoblephus puniceus. For both species, no evidence of genetic structuring, nor significant variation in genetic diversity, was found in the study area. Estimates of contemporary Ne were significantly lower in the protogynous species, but the same pattern was not apparent over historical timescales. Overall, our results show that sequential hermaphroditism may affect Ne differently over varying time frames, and that demographic signatures inferred from genetic markers with different inheritance modes also need to be interpreted cautiously, in relation to sex-changing life histories.
authors: Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven (KU Leuven), Leuven, Belgium.
authors: I
authors: I
authors: Coscia
authors: School of Biology and Environmental Science, University College Dublin, Dublin, Ireland.
authors: J
authors: J
authors: Chopelet
authors: NOAA Fisheries, Northwest Fisheries Science Center, Seattle, WA, USA.
authors: R S
authors: RS
authors: Waples
authors: Oceanographic Research Institute, Durban, South Africa.
authors: B Q
authors: BQ
authors: Mann
authors: Ecosystems and Environment Research Centre, School of Environment and Life Sciences, The University of Salford, Greater Manchester, UK.
authors: S
authors: S
authors: Mariani
mesh_terms: D000818:Animals; D004272:DNA, Mitochondrial / Q000235:genetics; D005260:Female; D014644:Genetic Variation; D005828:Genetics, Population / Q000379:methods*; D000071421:Life History Traits; D015810:Linkage Disequilibrium; D008297:Male; D018895:Microsatellite Repeats; D011156:Population Density; D012098:Reproduction; D021541:Sea Bream / Q000235:genetics* / Q000502:physiology*; D017422:Sequence Analysis, DNA; D019849:Sex Determination Processes; D012744:Sex Ratio; D013019:South Africa
chemical_list: D004272:DNA, Mitochondrial