3.3 Transfer and Ribosomal RNA Genes
Each of the 3 skipper species harbor 22 tRNA genes, 14 of which
(trnM ,trnI , trnW , trnL2 , trnK , trnD ,trnG , trnA , trnR , trnN , trnS1 ,trnE , trnT , trnS2 ) are encoded in the J-strand and
8 of them
(trnQ ,trnC , trnY , trnF , trnH , trnP ,trnL1 , trnV ) are encoded in the N-strand, ranging from 63
bp to 69 bp in size (Table 2). The total lengths of the tRNA region ofA.virgata , H.nephele and O.maga are 1,458bp,
1,460bp and 1,457bp, respectively. The AT content of tRNA is slightly
higher than that of the PCGs (Table 3). Most tRNA genes of these 3
mitogenomes could be folded into a cloverleaf secondary structure,
except for trnS (AGN), which lacks the DHU arm (Figure 3). The
total number of unmatched base pairs found in the tRNAs of the 3
skippers was 28 in O. maga , 29 in A. virgata and 34 inH. nephele . Most of these unmatched base pairs occur on the amino
acid acceptor arm, the DHU arm and the anti-codon arm, with only a few
occurring on the TΨC arm. The majority of unmatched base pairs is U-G
which is a semicompensatory substitution; the others being U-U A-C, U-C,
A-A, and A-G mismatches (Figure 3).
The 2 rRNA genes (rrnL , rrnS ) encoded by the N-strand are
located between trnL (CUN) and trnV , and betweentrnV and the AT-rich region respectively. The large subunit rRNA
(rrnL ) is 1,382/1,377/1,382 bp
(A.virgata/H.nephele/O.maga , respectively) in length while the
small subunit rRNA (rrnS ) is 770/768/772 bp (Table 2). In
addition, both tRNA and rRNA of the three mitogenomes show a strong AT
bias, which is higher than that of the whole mitogenomes (Table 3).