Complete mitochondrial genome of Trimeresurus albolabris (Squamata: Viperidae: Crotalinae)

The genome assembly and annotation of the white-lipped tree pit viper Trimeresurus albolabris

Trimeresurus albolabris, also known as the white-lipped pit viper or white-lipped tree viper, is a highly venomous snake distributed across Southeast Asia and the cause of many snakebite cases. In this study, we report the first whole genome assembly of T. albolabris obtained with next-generation sequencing from a specimen collected in Mengzi, Yunnan, China. After genome sequencing and assembly, the genome of this male T. albolabris individual was 1.51 Gb in length and included 38.42% repeat-element content. Using this genome, 21,695 genes were identified, and 99.17% of genes could be annotated using gene functional databases. Our genome assembly and annotation process was validated using a phylogenetic tree, which included six species and focused on single-copy genes of nuclear genomes. This research will contribute to future studies on Trimeresurus biology and the genetic basis of snake venom.

A comparison of gene organisations and phylogenetic relationships of all 22 squamate species listed in South Korea using complete mitochondrial DNA

Studies using complete mitochondrial genome data have the potential to increase our understanding on gene organisations and evolutionary species relationships. In this study, we compared complete mitochondrial genomes between all 22 squamate species listed in South Korea. In addition, we constructed Maximum Parsimony (MP), Maximum Likelihood (ML) and Bayesian Inference (BI) phylogenetic trees using 13 mitochondrial protein-coding genes. The mitochondrial genes for all six species in the suborder Sauria followed the same organisation as the sequenced Testudines (turtle) outgroup. In contrast, 16 snake species in the suborder Serpentes contained some gene organisational variations. For example, all snake species contained a second control region (CR2), while three species in the family Viperidae had a translocated tRNA-Pro gene region. In addition, the snake species, Elapheschrenckii, carried a tRNA-Pro pseudogene. We were also able to identify a translocation of a tRNA-Asn gene within the five tRNA (WANCY gene region) gene clusters for two true sea snake species in the subfamily Hydrophiinae. Our BI phylogenetic tree was also well fitted against currently known Korean squamate phylogenetic trees, where each family and genus unit forms monophyletic clades and the suborder Sauria is paraphyletic to the suborder Serpentes. Our results may form the basis for future northeast Asian squamate phylogenetic studies.

Complete mitochondrial genome of Sinovipera sichuanensis (Reptilia: Squamata: Viperidae)

Sinovipera sichuanensis is one of the Asian green pit vipers with less concern. It is endemic to China and only known in Hejiang, Sichuan Province and Jiangkou, Guizhou Province. In this study, we report the complete mitochondrial genome and characterize each partition. The complete mitochondrial genome is 17 225 bp in length containing 2 rRNAs, 13 protein-coding genes, 2 control regions and 22 tRNAs. We use Bayesian Inference (BI) and Maximum Likelihood (ML) methods to infer the phylogenetic relationship of S. sichuanensis. Both BI and ML analyses strongly support that S. sichuanensis is independent from the other two Asian green pit vipers.