A population genetic analysis of the New Zealand spotty (Notolabrus celidotus) using mitochondrial DNA and microsatellite DNA markers
Notolabrus celidotus (the New Zealand spotty) is a common rocky reef species that is endemic to New Zealand. This species is the most abundant demersal reef fish in New Zealand, and is distributed throughout the North and South Islands, and Stewart Island. Notolabrus celidotus consumes a wide variety of small invertebrates, and juveniles are reliant on coastal kelp forests as nursery habitats. Because N. celidotus is such a common species on New Zealand rocky reefs it is a good model species for population genetic studies. The primary goal of this research was to investigate new genetic markers and add new sample locations to bolster previous genetic population data from N. celidotus. The thesis research utilised DNA sequences obtained from a 454 massively parallel DNA sequencer and reports six new microsatellite loci for N. celidotus. These loci are the first microsatellite DNA markers to be developed for this species. Additional mitochondrial DNA (mtDNA) control region sequences were obtained from new samples of N. celidotus and combined with previously reported mtDNA sequences. Increasing the sample size improved the genetic coverage of N. celidotus populations around coastal New Zealand. The mtDNA sequences were analysed to examine the population connectivity and demographic history of N. celidotus. The microsatellite DNA loci reported in this study were also used to examine the levels of genetic diversity and population structure in N. celidotus. Results of the combined genetic analyses revealed extremely high levels of genetic diversity among the population sample of the mtDNA control region. Both the mitochondrial DNA and microsatellite DNA analyses showed a distinct lack of population genetic structuring, which suggests there is constant mixing of N. celidotus among sites. The results of this study have the potential to inform the expectations about the genetic structure of closely related wrasse species, such as Notolabrus fucicola, as well as other coastal species that have a similar life history, dispersal power, and New Zealand-wide distribution.