Fig. 3
Characteristics of unique intergenic spacers in 13 bothid mitogenomes. a: Grey boxes indicate the non-transcribed genes located in the intermediate dimeric molecule. b: Dark grey boxes indicate the numbered intergenic spacers. Fourteen loci are numbered as 1 to 12 plus two repeated spacers labeled 6′ and 10′. The lines between images a and b indicate that the non-transcribed genes in image a degenerated to intergenic spacers in image b; the pair of blue and brown lines indicate alternative results of degeneration of each underlined non-transcribed genes, respectively. The symbol of 
indicates regions of non-transcribed genes. The purple box indicates the OL formed by the middle sequence of tRNA-N, and the green box indicates the OL formed by an intergenic spacer and 3–5 bp from the 3′ end of tRNA-N. The tRNA-V and tRNA-D in solid and dotted boxes represent the alternative location in four species. c: The length of intergenic spacers. Abbreviations of species names are given as follows, P.co: Pleuronichthys cornutus; G.p: Grammatobothus polyophthalmus; A.t: Arnoglossus tenuis; L.g: Lophonectes gallus; L.l: Laeops lanceolate; P.i: Psettina iijimae; C.az: Crossorhombus azureus; C.ko: Crossorhombus kobensis; C.va: Crossorhombus valderostratus; A.po: Arnoglossus polyspilus; B.my: Bothus myriaster; C.lu: Chascanopsetta lugubris; A.in: Asterorhombus intermedius; and B.pa: Bothus pantherinus. The number in parentheses after the species names is the amount of unique intergenic spacers. Below intergenic spacer No. 3, length of spacers between OL and COI are indicated in black numbers, and that between tRNA-N and COI indicated in dark red. The light brown numbers indicate the length of intergenic spacers that have no relationship to the DMNL process