Table 1.

The genome features and gene content of 12 mtDNAs in the class Mediophyceae belonging to the Phylum Bacillariophyta. The strains indicated in blue were obtained in this study

Species	Strains	Habitat	Accession number	Size(bp)	A + T(%)	PCGs/rRNAs	rps2	rrn5	tRNA	Introns	Start codon of atp8	Reference
Skeletonema marinoi	CNS00100	Marine	MW438984	38,773	70.3	34/2	+	–	25	0	GTG	This study
Skeletonema marinoi	JK029	Marine	NC_028615	38,515	70.3	34/2	+	–	25	0	GTG	[45]
Skeletonema tropicum	CNS00166	Marine	MW438983	37,543	70.6	34/2	+	–	25	0	ATA	This study
Skeletonema costatum	CNS00243	Marine	MW438982	40,676	71.5	34/2	+	–	26	0	TTA	This study
Skeletonema costatum	CNS00303	Marine	MW438981	40,675	71.5	34/2	+	–	26	0	TTA	This study
Skeletonema pseudocostatum	CNS00342	Marine	MW438980	36,199	70.6	34/2	+	–	25	0	ATA	This study
Skeletonema grevillei	CNS00438	Marine	MW438979	36,336	70.8	34/2	+	–	25	0	TTA	This study
Thalassiosira pseudonana		Marine	NC_007405	43,827	69.9	34/2	+	–	25	1	TTA	[47]
Thalassiosira profunda	CNS00050	Marine	MW013551	40,470	69.0	34/2	+	–	25	0	ATT	[48]
Odontella regia	CNS00380	Marine	MW018491	37,617	73.4	34/2	–	+	24	0	ATG	[43]
Lithodesmium undulatum	CNS00316	Marine	MW023083	37,057	75.3	34/2	–	+	25	0	ATT	[43]
Toxarium undulatum	ECT3802	Marine	NC_037988	40,429	69.9	34/2	+	–	26	0	ATG	[49]

The core genes included 34 PCGs (atp6, 8, 9; cob; cox1, 2, 3; nad1–7, 4 L, 9, 11; rpl2, 5, 6, 14, 16; rps 3, 4, 7, 8, 10, 11, 12, 13, 14, 19; and tatA, tatC) and two rRNAs