Complete sequence and gene organization of the mitochondrial genome of Siamensis Crocodile (Crocodylus siamensis).

The complete sequence of mitochondrial genome of Siamensis Crocodile (Crocodylus siamensis) is determined by using PCR amplification, clone and primer-walking sequencing methods. The genome is 16836 bp in size, containing 13 protein-coding, 2 ribosomal and 22 transfer RNA genes. The mtDNA genome of Siamensis Crocodile is similar to most vertebrates in gene component, order, orientation, tRNA structure, low percentage of guanine and high percentage of thymine. The nonstandard stop codes (T) in two protein genes (Cox III and Cyt b) are more than those of most vertebrates. Transfer RNA genes range in length from 61 to 76 nucleotides, and their planar structure present characteristic clover leaf, except for tRNA-Ser (AGY) because of lacking the "DHU" arm.