The population genetic structure of the waratah anemone (Actinia tenebrosa) around New Zealand

Abstract

The genetic structure of populations is often shaped by the reproductive system and larval properties of the species. The waratah anemone (Actinia tenebrosa) reproduces through both asexual clones, which have very short-distance dispersal, and sexual larvae, which are believed to disperse much greater distances. The impact of this mixed strategy on the New Zealand population structure of Actinia tenebrosa was investigated using microsatellite markers. The analysis incorporated 24 sampling locations from around New Zealand and one Australian location, using four microsatellite markers, n 0420. We observed low connectivity and high genetic differentiation between all locations sampled, with a distinct pattern of isolation by distance. The most distinct grouping of locations sampled was the north-east of the North Island from Cape Reinga to East Cape, which was identified by SAMOVA and STRUCTURE analyses as being moderately diverged from the remainder of the country. A tentative correlation was observed between genetic clustering and biogeographic regionalisation, where the distribution of a number of genetic clusters matched previously defined biogeographic regions. Within each location sampled, large numbers of clones were present and a latitudinal cline was observed in the relative contribution of asexually and sexually generated recruits, with an increase in asexual recruits on the South Island's east coast.

Contrasting patterns of population structure and demographic history in cryptic species of Bostrychia intricata (Rhodomelaceae, Rhodophyta) from New Zealand

“…) and a genetic split between western/eastern regions, especially on the South Island ( B. intricata N4 groupings 5, 6 vs. 3, 4; Jones et al. , Veale and Lavery , Fig. ).…”

Population structure and dispersal across small and large spatial scales in a direct developing marine isopod

“…Strait. Instead, we observe high gene flow over the East Cape, and genetic clustering of 308 locations has been found for the anemone Actinia tenebrosa (Veale & Lavery, 2012). 310…”

“…Stevens & Hogg, 2004;Veale & Lavery, 2012). Even 294 population structure in biphasic species with larval stages, such as the paua Haliotis iris(Will 295 et al, 2011), and the marine gastropod Buccinulum vittatum(Gemmell et al, 2018), are 296 affected by the East Cape.…”

Discordance between nuclear and mitochondrial DNA analyses of population structure in closely related triplefin fishes (Forsterygion lapillum and F. capito, F. Tripterygiidae) supports speciation with gene flow

“…While this is broadly consistent with mtDNA results for these species, especially F. capito, and some north-south differences between the Islands were found in some of the other triplefin species examined (Hickey et al 2009), such divergence was not the major population division seen with mtDNA in either F. lapillum or F. capito. A genetic disjunction near Cook Strait has been found in a number of marine invertebrate taxa (Ross et al 2012;Veale and Lavery 2012;Wei et al 2013), suggesting it may be a common barrier to gene flow. The trend has been attributed to upwelling currents reducing larval transport between the islands (Goldstien et al 2006;Veale and Lavery 2012).…”

“…A genetic disjunction near Cook Strait has been found in a number of marine invertebrate taxa (Ross et al 2012;Veale and Lavery 2012;Wei et al 2013), suggesting it may be a common barrier to gene flow. The trend has been attributed to upwelling currents reducing larval transport between the islands (Goldstien et al 2006;Veale and Lavery 2012). In our data, however, even though there is some apparent differentiation between northern and southern populations, this may be due to IBD or other factors, as it appears that the Cook Strait does not represent a major barrier to gene flow in these triplefin species.…”