Identification of Labeo rohita, L. bata and L. gonius is sometimes problematic when usual morphological features are lost and it is difficult to differentiate them with traditional morphological features at their diverse developmental stages. PCR-sequencing provides an authentic alternative means of identification of individuals at species level. Three local carp fishes were collected and 16S rRNA genes were sequenced by sanger sequencing method after PCR amplification using universal primers. Obtained sequences were found accurate with blast search result which showed maximum range of similarity with the existing respective gene fragments present in GenBank database. Sequences were compared and multiple sequence alignment has revealed some polymorphic sites which can be used to differentiate these three species from one another. This study may provide valuable understanding to study their population in future. Dhaka Univ. J. Biol. Sci. 26(2): 167-174, 2017 (July)

Copy’s frog, commonly observed in Bangladesh, is ecologically important for evergreen forest. Sample was collected from Satchari National park, Hobigonj, Sylhet. Attempts were made to combine morphological and molecular techniques for identification and analysis of evolutionary relation of Copy’s frog with anuran species. Morphological identification of Hydrophylax sp. was conducted based on distinguishing characteristics of the body and different body measurement parameter. The species was identified morphologically as Hydrophylax leptoglossa based on the taxonomic key of finger toes and formula was 3>1>4>2. Simultaneously genomic DNA was isolated using CTAB extraction method. The 16S rRNA gene was amplified from the genomic DNA by polymerase chain reaction method using the pair of universal primers. Amplified product was a 308 bp fragment that generated AT/GC ratio of 1.08% once sequenced. In the present study comparative analysis of intraspecific and interspecific variation was conducted based on nucleotide sequence of 16S rRNA gene collected from GenBank. The intraspecific variation compares between Southeast Asia and Bangladesh was 1.29% for 16S rRNA gene. The interspecific genetic divergence was studied between H. leptoglossa and H. tytleri was observed 14.29%. The nucleotide sequence of the present study will be used as DNA barcode for that particular individual collected from Sylhet, Bangladesh. Furthermore, a molecular phylogenetic tree was constructed, where all the anuran species from a monophyletic group. Four species of Hydrophylax form monophyletic group and is consistent with relation based on morphology. Bangladesh J. Zool. 49(1): 105-115, 2021

DNA barcoding has been proposed as a means of quick species identification using a short standardized segment of DNA. Two species (Eleotris fusca and Glossogobius giuris) from the family Gobiidae and Eleotridae were selected for DNA barcoding using samples collected from different regions of Bangladesh. Cytochrome Oxidase Subunit I (COI) gene was sequenced from two different gobi fishes and compared with two previously published similar sequences from the genera Eleotris and Glossogobius. Multiple sequence alignment and the molecular systematic study were performed. The DNA barcode technique identified the two species. The study provides a good example of how DNA barcoding can build upon its primary mission of species identification and use available data to integrate genetic variation investigated at the local scale into a global framework.

Global amphibian populations are facing a novel threat, chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), which is responsible for the severe decline of a number of species across several continents. Chytridiomycosis in Asia is a relatively recent discovery yet there have been no reports on Bd-presence in Bangladeshi amphibians. We conducted a preliminary study on 133 wild frogs from seven sites in Bangladesh between April and July 2018. Nested PCR analysis showed 20 samples (15.04%) and 50% of the tested taxa (9 species from 6 genera and 4 families) as Bd-positive. Eight of the nine species are discovered as newly infected hosts. Analysis of Bd-positive samples shows prevalence does not significantly vary among different land cover categories, although the occurrence is higher in forested areas.The prevalence rate is similar in high and low disturbed areas but the range of occurrence is statistically higher in low disturbance areas. Maximum entropy distribution modelling indicates high probabilities of Bd occurrence in hilly and forested areas in south-east and central-north Bangladesh. The Bd-specific ITS1-5.8S-ITS2 ribosomal gene sequence from the Bd-positive samples tested is completely identical. A neighbor-joining phylogenetic tree reveals that the identified strain shares a common ancestry with strains previously discovered in different Asian regions. Our results provide the first evidence of Bd-presence in Bangladeshi amphibians, inferring that diversity is at risk. The effects of environmental and climatic factors along with quantitative PCR analysis are required to determine the infection intensity and susceptibility of amphibians in the country.