Genetic Diversity and Geographical Distribution of the Red Tide Species Revealed Using a High-Resolution Molecular Marker.

Diatoms are responsible for approximately 40% of the global primary photosynthetic production and account for up to 20% of global carbon fixation. is a red tide forming species of the phylum Bacillariophyta that has been detected in a wide range of coastal regions, suggesting the possibility of the existence of high genetic diversity with differential adaptation. Common molecular markers including 18S rDNA, 16S rDNA, ITS, , and do not provide sufficient resolution for distinguishing intra-species genetic diversity, hindering in-depth research on intra-species genetic diversity and their spatial and temporal dynamics. In this project, we aimed to develop molecular markers with high resolution and specificity for , attempting to identify different taxa of this species, which will set up a stage for subsequent functional assays. Comparative genomics analysis of the mtDNAs of strains identified a genomic region with high genomic variations, which was used to guide the development of a molecular marker with high resolution and high specificity. This new molecular marker, which was named ( mitochondrial 1), was 376 bp in size and differentiated samples collected in coastal regions of China into three different clades. Preliminary analysis of field samples collected in various coastal regions in China revealed that clades were almost exclusively found in the Bohai Sea and the north Yellow Sea. This newly developed molecular marker could be used for tracking intra-species genetic diversity and biogeographic distribution of in different ecosystems.