Comparative mitogenomics of Agaricomycetes: Diversity, abundance, impact and coding potential of putative open-reading frames

Mitochondrial Genomic Landscape: A Portrait of the Mitochondrial Genome 40 Years after the First Complete Sequence

“…The protein-encoding genes are well conserved in the three main kingdoms: 14 in the Fungi, 13 in the Metazoa (excluding non-bilaterians), and 24 in the Viridiplantae [ 151 ]. The higher standard deviation of the gene content in Viridiplantae and Fungi ( Figure 2 b) is mainly due to the homing endonucleases encoded inside the introns and unassigned ORFs [ 82 , 152 , 153 ].…”

“…A handful of tRNAs have been identified in cnidarians (e.g., [78,123]), where additional genes are present ( [124] and references therein); similarly, many genes that are usually found in animal mtDNA are missing from that of ctenophores (tRNAs, atp6, atp8; [79,81,116,125]). This summary of mitochondrial molecular structures and architectures certainly gives an idea of the stunning variability of these organellar genomes, which largely surpasses that of plastid trans-splicing phenomena [19,78,81,126]; the use of different genetic codes [13,127,128]; bewildering gene rearrangement [81][82][83][84][85][86][87][88]105,106,[129][130][131]; and biparental and doubly uniparental inheritance [28,30,58,[132][133][134][135][136].…”

“…Genome size. Genome size is highly variable among eukaryotes, ranging from 6 kb in apicomplexan [ 23 , 24 , 72 , 73 ] and <13 kb in some green algae [ 77 ], ctenophores [ 78 , 79 ], and some fungi [ 80 ]; through 43 kb in placozoans [ 78 , 81 ] and >70 kb in choanoflagellates and ciliates [ 57 , 76 ]; up to >200 kb in other green algae and fungi [ 82 , 83 , 84 ], and 11 Mb in flowering plants [ 38 ]. Moreover, phenomena of the punctuated expansion of mtDNA have been reported within clades with generally reduced genome size (e.g., frogs [ 85 ], ark shells [ 86 , 87 ]).…”

“…Moreover, phenomena of the punctuated expansion of mtDNA have been reported within clades with generally reduced genome size (e.g., frogs [ 85 ], ark shells [ 86 , 87 ]). In most cases, this variability is not related to gene content; rather, the expansion and reduction of the intergenic region appear to be the main drivers of genome size among eukaryotes (e.g., [ 38 , 56 , 58 , 82 , 83 , 88 , 89 ]).…”

“…This summary of mitochondrial molecular structures and architectures certainly gives an idea of the stunning variability of these organellar genomes, which largely surpasses that of plastid trans-splicing phenomena [ 19 , 78 , 81 , 126 ]; the use of different genetic codes [ 13 , 127 , 128 ]; bewildering gene rearrangement [ 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 105 , 106 , 129 , 130 , 131 ]; and biparental and doubly uniparental inheritance [ 28 , 30 , 58 , 132 , 133 , 134 , 135 , 136 ].…”