Complete mitochondrial genome of “Xenopus tropicalis” Asashima line (Anura: Pipidae), a possible undescribed species

Abstract

The diploid Xenopus tropicalis, with its small nuclear genomic size and short generation time compared to the traditional experimental amphibian X. laevis, is considered a next-generation model animal. Several experimental X. tropicalis lines have been used in research studies. Previous studies showed that the mtDNA sequence of the Asashima line is divergent from other lines and that this line may represent a distinct species. Here, we report the complete nucleotide sequence of this unique X. tropicalis experimental line. The genome is 17,700 bp in length and contains 37 genes commonly found in animal mtDNAs. The 16S rRNA gene sequence in Asashima line differed by over 6% from the standard Nigerian lines (a 3% difference is considered the species threshold in anurans), suggesting that this experimental line is a distinct species from the true X. tropicalis.

• Asashima line
• experimental animal
• mitochondrial genome
• Xenopus tropicalis

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. This study was supported by Japan Society for Promotion of Science (JSPS) Grants-in-Aid for Scientific Research (KAKENHI), grant #24590232 and #21241048. Xenopus tropicalis Asashima line used in this study was maintained under National Bio-Resource Project of the MEXT, Japan.