Mitogenome features and phylogenetic analysis of red algae, Grateloupia cornea (Rhodophyta, Halymeniales)

The mitogenome is an important tool for taxonomic and evolutionary investigation. Here, a few complete mitogenomes of red algae have been reported. We have reported the complete mitogenome sequences of Grateloupia cornea Okamura, 1913 (Rhodophyta, Halymeniales). The genome is 30,595 bp in circumference, and has a strongly biased [AT] = 66.9%. Like most other Grateloupia species, it has a group II intron in the cox1 gene. Maximum likelihood and maximum parsimony analyses showed that G. cornea is more closely related to G. asiatica. This shows that the group II intron in the cox1 ORF present in most species of Grateloupia was present in their common ancestor, and uniquely lost in G. asiatica. The seven Grateloupia species with known mitogenome sequences remain monophyletic, with the genus Polyopes as sister taxon. The complete mitochondrial genome data will be valuable for future research on comparative mitochondrial genome analysis, an extensive understanding of gene content and organization, evolution of the cox1 intron in Rhodophyta as well as phylogenetic analysis.