Abstract
Tuatara (Sphenodon spp) populations are restricted to 35 offshore islands in the Hauraki Gulf, Bay of Plenty and Cook Strait of New Zealand. Low levels of genetic variation have previously been revealed by allozyme and mtDNA analyses. In this new study, we show that six polymorphic microsatellite loci display high levels of genetic variation in 14 populations across the geographic range of tuatara. These populations are characterised by disjunct allele frequency spectra with high numbers of private alleles. High F ST (0.26) values indicate marked population structure and assignment tests allocate 96% of all individuals to their source populations. These genetic data confirm that islands support genetically distinct populations. Principal component analysis and allelic sequence data supplied information about genetic relationships between populations. Low numbers of rare alleles and low allelic richness identified populations with reduced genetic diversity. Little Barrier Island has very low numbers of old tuatara which have retained some relictual diversity. North Brother Island’s tuatara population is inbred with fixed alleles at 5 of the 6 loci.
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Acknowledgements
We thank the teams of biologists from Victoria University, the Department of Conservation and numerous volunteers who collected the tuatara samples. We also thank Dr Jenny Hay for donating the North and South Trios DNA samples we used and Sue Keall, Dr Nicky Nelson, Kelly Hare and Joanna Hoare for providing historical and biological information about tuatara on North Brother Island and translocations. We are grateful to Rod Lea who introduced us to the Structure analysis program and to Lesley Milicich who helped with DNA sequencing runs during the early development of the microsatellites. This study was supported by the Victoria University of Wellington Research Fund.
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MacAvoy, E.S., McGibbon, L.M., Sainsbury, J.P. et al. Genetic variation in island populations of tuatara (Sphenodon spp) inferred from microsatellite markers. Conserv Genet 8, 305–318 (2007). https://doi.org/10.1007/s10592-006-9170-5
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DOI: https://doi.org/10.1007/s10592-006-9170-5