Deep-water sea anemone with a two-chromosome mitochondrial genome

Mitochondrial Group I Introns in Hexacorals Are Regulatory Genetic Elements

“…Mitochondrial RNAs have been investigated in a few hexacoral species representing sea anemones, colonial anemones, and mushroom corals [6,12,[14][15][16]. RNAseq data were obtained from 454 pyrosequencing and Ion Torrent PGM sequencing.…”

“…Information from our unpublished complete mitochondtial genome sequence of Stichodactyla helianthus. 6 The black coral Cirrhipathes lutkeni may also be annotated as Strichpates lutkeni.…”

“…Furthermore, it was noted that robust-clade species have developed a highly compact ribozyme core compared to complex-clade species (and all other hexacorals) [19]. The most complex ND5-717 introns are found in mushroom corals and in the Protanthea sea anemone [6,16,28,30]. Whereas three versions of 9, 11, and 15 intron-located genes are noted in mushroom corals, 14 genes are present in P8 of Protanthea (Figure 2B and C).…”

“…Hexacorals have a global marine distribution pattern typically recognized in tropical seas at shallow waters living in close relationships with endosymbiotic photosynthetic alga. However, coral reefs and sea anemones in deep offshore waters have more recently been investigated [3][4][5][6]. These cold-water hexacorals occur in low temperatures at high latitudes or great depths.…”

“…The shortest forms of ND5-717 introns (approximately 1.6-2.4 kb) detected in sea anemones, colonial anemones, and black corals are likely to be excised by conventional group I intron cis-splicing from one single precursor RNA ( Figure 4A). The longest forms of ND5-717 introns (approximately 15-19 kb), present in mushroom corals [28,30] and the deep-water Protanthea sea anemone [6], contain almost the entire mitochondrial genome within P8. Recently, experimental support of intron removal by backsplicing in mushroom corals was reported [16].…”