Development of ten microsatellite markers for Alexandrium ostenfeldii, a bloom-forming dinoflagellate producing diverse phycotoxins

Alexandrium ostenfeldii is a globally distributed dinoflagellate species capable of producing several potent toxins. Blooms of this species are presently expanding, possibly as a result of changing environmental conditions or recent spreading of geographically distant populations. Population genetic analyses are a useful tool to investigate invasion and selection as potential mechanisms behind the global increase in toxic algal bloom events. In this study, we isolated ten polymorphic microsatellite markers from A. ostenfeldii by three techniques, two PCR-based techniques, and a next generation sequencing technique. To characterize the newly developed microsatellite loci, DNAs extracted from 40 clonal isolates of Baltic A. ostenfeldii were genotyped. The isolated microsatellite loci were shown to be sufficiently polymorphic; allele numbers ranged from 2 to 12 among the studied strains, and estimates of gene diversity varied between 0.10 and 0.92. The ten polymorphic genetic markers developed in this study will facilitate investigations on genetic structure and gene flow within and among A. ostenfeldii populations, as well as studies on the role of selection by changing environmental conditions in bloom formation.