Tracing Invasions of Caulerpa Taxifolia with Molecular Markers

摘要: Comparative sequence data from the rDNA ITS have proven very useful in species identification and identifying major biogeographic groups of Caulerpa taxifolia. However, low variability sequence, need to screen hundreds samples has limited its utility for population level studies. Here we report on performance two new markers suitable screening: chloroplast 16S intron-2 intersimple-sequence-repeat fingerprints (ISSRs). A analysis ITS1 insertion–deletion patterns was also conducted using all available sequences. number insights emerged. First, invasive aquarium strain (Mediterranean, California) is clearly Brisbane, but Brisbane populations themselves may be result an introduction Northern Australia. Second, conjunction with ITS1-insertion–deletion further suggests that Mediterranean not one, separate introductions. Third, intrapopulation genetic diversity between ‘native’ Australian revealed occurrence divergent widespread clades. The first clade grouped nontropical coastal inshore Australia while second clustered offshore/oceanic so far studied. C. taxifolia, therefore exists as a complex independent ecotypes probably represent nascent species. Fourth, despite our finding nine distinct nuclear five profiles, strong linkage disequilibrium found most specimens, which indicates predominance asexual reproduction. nucleo-cytoplasmic recombination detected one case, supporting hybridization both within populations.