RESUMEN
Identification of elasmobranchs by conventional taxonomy is difficult due to similarities in morphological characters. Species-specific molecular markers are good choice for identifying species irrespective of it's life stage. Recently, mitochondrial cytochrome c oxidase subunit I (COI) gene got global recognition as a barcode gene to discriminate all animals up-to species level. In this study, mitochondrial COI partial gene was used to develop DNA barcodes for 18 species of elasmobranchs (10 species of sharks and 8 species of rays). The COI barcodes clearly distinguished all the species with high interspecific distance values than intraspecific values. The average interspecific and intraspecific distance values are 8.6% and 0.3% for sharks, respectively and 12.4% and 0.63% for rays, respectively using K2P method. The Neighbor-Joining tree showed distinct clusters shared by the species of same genera. The COI barcodes were also used to estimate allopatric divergences for selected species across broad geographical locations and found that Sphyrna lewini, Aetobatus narinari and Neotrygon kuhlii have cryptic diversity.
Asunto(s)
Código de Barras del ADN Taxonómico , Elasmobranquios/clasificación , Elasmobranquios/genética , Complejo IV de Transporte de Electrones/genética , Genes Mitocondriales , Animales , Composición de Base , Complejo IV de Transporte de Electrones/química , Variación Genética , India , Filogenia , Filogeografía , Análisis de Secuencia de ADNRESUMEN
The elasmobranchs (sharks, rays and skates) being the extant survivors of one of the earliest offshoots of the vertebrate evolutionary tree are good model organisms to study the primitive vertebrate conditions. They play a significant role in maintaining the ecological balance and have high economic value. Due to over-exploitation and illegal fishing worldwide, the elasmobranch stocks are being decimated at an alarming rate. Appropriate management measures are necessary for restoring depleted elasmobranch stocks. One approach for restoring stocks is implementation of conservation measures and these measures can be formulated effectively by knowing the evolutionary relationship among the elasmobranchs. In this study, a total of 30 species were chosen for molecular phylogeny studies using mitochondrial cytochrome c oxidase subunit I, 12S ribosomal RNA gene and nuclear Internal Transcribed Spacer 2. Among different genes, the combined dataset of COI and 12S rRNA resulted in a well resolved tree topology with significant bootstrap/posterior probabilities values. The results supported the reciprocal monophyly of sharks and batoids. Within Galeomorphii, Heterodontiformes (bullhead sharks) formed as a sister group to Lamniformes (mackerel sharks): Orectolobiformes (carpet sharks) and to Carcharhiniformes (ground sharks). Within batoids, the Myliobatiformes formed a monophyly group while Pristiformes (sawfishes) and Rhinobatiformes (guitar fishes) formed a sister group to all other batoids.
Asunto(s)
Elasmobranquios/genética , Genes Mitocondriales , Animales , Composición de Base , Teorema de Bayes , ADN Espaciador Ribosómico/genética , Complejo IV de Transporte de Electrones/genética , Proteínas de Peces/genética , Marcadores Genéticos , Funciones de Verosimilitud , Modelos Genéticos , Tipificación de Secuencias Multilocus , Filogenia , ARN Ribosómico/genética , Análisis de Secuencia de ADNRESUMEN
Nasal polypectomy is a common ENT operation. Cerebrospinal fluid (CSF) rhinorrhoea and pneumocephalus are rare complications. We present a patient who developed both these complications after biopsy of nasal polyps which subsequently proved to be an inverted papilloma. He had a defect in the ethmoid roof, which was repaired. Whilst endoscopic repair of CSF leak is increasing in popularity, in this patient because of his pathology and difficulty of access a more traditional lateral rhinotomy approach was made with a successful outcome. An overview of the management of these complications is presented.
