New microsatellite markers for the seagrass Amphibolis antarctica reveal unprecedented genetic diversity

The limited data available on the genetic diversity of the temperate seagrass Amphibolis antarctica indicate diversity may be extremely low. The available previous study was based on allozymes and restriction fragment length polymorphisms (RFLPs) as molecular markers. Numerous studies into other seagrass taxa have shown that these markers may not have the appropriate sensitivity to reveal genetic diversity. In order to determine if A. antractica is genuinely genetically depauperate, or if the genetic markers used were not suitable to capture the diversity, we developed novel microsatellites for this species. Forty-eight primer candidates were screened with a limited number of geographically diverse samples. Fourteen loci displayed adequate polymorphism and were arranged into three multiplex PCR panels for further testing. DNA samples of four populations were tested and statistics on locus population and genotypic diversity calculated. This is the first study that has found genetic diversity within A. antarctica, with allele numbers ranging between 2-10 per locus. Expected heterozygosity (HE) for the four populations ranged between 0.355-0.507. This small-scale study has given the first insight into the genetic diversity of this species and has provided a tool to evaluate life-history strategies such as clonality, reproduction and dispersal of one of the most important southern Australian seagrass species.