Molecular phylogenetics of Black Cobra (Naja naja) in Pakistan

Background: Snakes are found on every continent in the world except Antarctica, and on smaller land masses. Being ecologically important, they also cause a large number of bites, leading to millions of deaths. Mitochondrial and nuclear gene sequences are being used to identify, characterize, and infer genetic biodiversity among different snake species. Furthermore, phylogenetics helps in inferring the relationships and evolutionary histories among these species. Black cobra is one of the four most venomous snakes in Pakistan. Four mitochondrial (ND4, Cytochrome b, 12S rRNA, and 16S rRNA) and four nuclear (C-mos, RAG-1, BDNF, and NT3) genes were used to trace diversity and infer the phylogenetic relationship of black cobra in Pakistan. Results: Almost similar phylogenies were obtained through maximum likelihood and Bayesian inference, showing two species of cobra in Pakistan, namely, black cobra (Naja naja) and brown cobra (Naja oxiana). All Naja species were divided into three clades: black cobra (N. naja) and brown cobra (N. oxiana) cladding with different species of Naja; N. naja (Pakistan) cladding with N. naja from Nepal; and N. oxiana showed close relationship with Naja kaouthia from Thailand and Naja siamensis from Thailand. Conclusion: It was confirmed genetically that there are two cobra species in Pakistan, i.e., black and brown cobras. This study will help in not only genetic conservation but also developing anti-venom against snake species.

Estudo cariotípico de duas espécies brasileiras do gênero Micrurus (Ophidia: Elapidae) / Karyotypic studies of two Brazilian species of the genus Micrurus (Ophidia: Elapidae)

Descrevemos neste trabalho o cariótipo de duas espécies de cobra coral (Ophidia: Elapidae) do Brasil: Micrurus corallinus e M. ibiboboca. Preparações citológicas foram obtidas através da técnica de esmagamento, seguida de coloração convencional com Giemsa. Encontramos para M. corallinus, um número diplóide (2n) de 40 cromossomos, com fórmula cariotípica 40 (4; 16; 20) e constricção secundária no segundo par de macrocromossomos subtelocêntricos. Micrurus ibiboboca apresentou 2n = 42, com fórmula cariotípica 42 (2; 20; 20) e constricção secundária no primeiro par de macrocromossomos telocêntricos. As primeiras descrições dos cariótipos das espécies M. corallinus e M. ibiboboca, apresentadas neste trabalho, mostram aspectos semelhantes aos cariótipos de M. lemniscatus e M. surinamensis, únicas espécies deste gênero da América do Sul analisadas cromossomicamente. As quatro espécies em questão apresentam o mesmo número de microcromossomos (20), os maiores valores de macrocromossomos telocêntricos ou subtelocêntricos e os maiores números diplóides (2n) já encontrados no gênero Micrurus. Tais características diferenciam estas espécies da América do Sul das nove da América Central com cariótipos já estudados.

The karyotypes of two brazilian species of coral snakes (Ophidia: Elapidae): Micrurus corallinus and M. ibiboboca are described for the first time. Cytological preparations were obtained through the technique of squashing, followed by conventional Giemsa staining. The diploid number for Micrurus corallinus was 40 chromosomes with a karyotype formulae 40 (4; 16; 20) with a secondary constriction in the second pair of subtelocentric macrochromosomes. Micrurus ibiboboca is described by the formulae 42 (2; 20; 20) with 2n = 42 with a secondary constriction in the first pair of telocentric macrochromosomes. The karyotypes of M. corallinus and M. ibiboboca present aspects similar to M. lemniscatus and M. surinamensis, the only previously analyzed species of this genus in South America. These four species have the same number of microchromosomes (20), the largest number of telocentric or subtelocentric macrochromosomes and the largest diploid numbers (2n) ever found in the genus Micrurus. These characteristics differ from those of the nine known species of Central America.