Characterization of the complete mitochondrial genome of Collared Finchbill, Spizixos semitorques (Passeriformes: Pycnonotidae)

The complete mitochondrial genome of Spizixos semitorques is 17,045 bp long with an A+T content of 55.52%, which composed of 13 typical protein-coding genes, 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes, and 2 extensive heteroplasmic control regions (CR1 and CR2). Genome organization of S. semitorques is similar to that of other birds. All of the PCGs started with ATG, except for cox1, which began with GTG. Six types of termination codons were used, canonical TAA and TAG termination codons are found in seven protein-coding genes, while AGA for nad1 and nad5, AGG for cox1, and the remaining genes (nad2, cox3, nad4) have incomplete termination codons (TA- or T- -). All tRNA genes have a typical clover-leaf structure. Furthermore, a minisatellite of 24 nucleotides (5'-CACAAAAATCAAACAAAAATACAA-3') with 2.9 tandem repeats at the end of CR2 were detected.