Population Genetic Structure of Sargassum horneri, the Dominant Species of Golden Tide in the Yellow Sea

Sargassum horneri golden tides are increasingly becoming a marine ecological problem in the Yellow Sea (YS) and East China Sea. To understand the genetic relationship between the attached S. horneri along the China coast and the floating biomass in the YS, we used partial rbcL, ITS2, cox1, cox3, and cob-cox2 to analyze the population genetic evolution of 165 Sargassum samples. The results showed that all samples were a single species of S. horneri. Partial sequences of each gene had major haplotypes, and other haplotypes evolved from the occurrence of base mutations. The cob-cox2 gene haplotype research showed only the attached samples from ZJ, LN, and KR contained Hap3, and the distribution proportions of Hap2 and Hap4 in SS and the YS were closest to the distribution of the attached samples from SD. These novel findings provided information about the genetic evolutionary relationship between attached S. horneri along the coast of China and floating S. horneri in the YS, as well as new ideas for tracing the source of floating S. horneri in the YS from a molecular biological perspective.