Complete mitochondrial genome of the brown alga Sargassum hemiphyllum (Sargassaceae, Phaeophyceae): comparative analyses.

Sargassum hemiphyllum (Turner) C. Agardh is a common low intertidal brown alga in the northwestern Pacific, and two varieties (var. chinense and var. hemiphyllum) of this alga have been determined based on morphological and molecular data. In this study, we present the complete mitochondrial genome of S. hemiphyllum var. chinense. The circular-mapping S. hemiphyllum mitogenome of 34,686 bp has an overall A+T content of 63.43%, and contains 65 densely packed genes. The total intergenic spacer regions are 1597 bp, constituting 4.60% of the mitogenome. The gene content and genome organization of S. hemiphyllum are identical to that of other reported Sargassum species. The identity comparison of overall mitogenome sequences and phylogenomic analyses indicate that S. hemiphyllum has a closer evolutionary relationship with Sargassum muticum than other Sargassum species analyzed. The present mitogenomic data provide a powerful tool for definition of varieties and studies of population structure in S. hemiphyllum.