Phylogeny Of Penaeid Shrimps And Population Genetic Structure Of The Green Tiger Prawn (Penaeus Semisulcatus) In Malaysian Waters

This study reports on the phylogeny of selected penaieds and population genetics of the commercially important Green Tiger Prawn (Penaeus semisulcatus) in the Malaysian waters. In the first part of this study, morphological shape variations among 12 species of family Penaeidae, mainly from northwest coast of Peninsular Malaysia were investigated. This was achieved based on the Geometric Morphometrics (GM) of 18 homologous landmarks, analysed with Principal Component Analysis (PCA) and Canonical Variate Analysis (CVA) in Morpho J software. The shape variations was attributed to body shape, carapace head and telson tail among individuals. The first four components accounted for 76.24% and 78.47% for PCA and CVA, respectively. There is a tendency for closely related species to cluster together, although not absolutely consistent. To assess the phylogenetic signal, the morphometric data was mapped onto three phylogenetic trees (Neighbour Joining -NJ, Maximum Likelihood- ML and Bayesian Inference- BI) generated from the partial mitochondrial Cytochrome oxidase Subunit 1 (COI) on the same 12 species. Results revealed non significance (no phylogenetic signal) for NJ but significant phylogenetic signal (evolutionary significance) for ML and BI which suggest shape difference among all 12 penaeid prawn species was related to their evolutionary history. This discrepancy could be explained due to NJ tree are prone to errors when dealing with deeper divergence times, whereas ML and BI tree are ideal for phylogeny tree reconstruction which apply a model of sequence evolution on the data

Morphometrics and meristics analyses of Cyprinid fishes, Cyclocheilichthys species from Batang Kerang Floodplain, Balai Ringin and Wilma Plantation, Suai, Sarawak

In this study, morphometric characters and meristic counts were used to investigate the morphological variations of Cyclocheilichthys apogon and Cyclocheilichthys armatus. There are a total of 56 specimens; Cyclocheilichthys apogon from Batang Kerang (n = 20) and Wilma Plantation, Suai (n = 7) and Cyclocheilichthys armatus from Wilma Plantation, Suai (n = 29). The ANOVA analyses revealed 15 morphometric and 3 meristic characters that differentiated Cyclocheilichthys apogon from Cyclocheilichthys armatus. A PCA was performed on 15 log transformed morphometric measurements which the first two factors contributed to 82.5% of total variability. The ANOVA also shows small variations of C. apogon between these two different locations. Thus, the classification of Cyclocheilichthys apogon and Cyclocheilichthys armatus shows successful differentiated

The complete mitochondrial genomes of Pangasius nasutus and P. conchophilus (Siluriformes: Pangasiidae)

The catfish, Pangasius nasutus and P. conchophilus, are often misidentified between each other due to their similar morphology. Thus, the current study was conducted to differentiate them based on a molecular approach. The complete mitochondrial genomes of P. nasutus and P. conchophilus obtained from the Pahang River (Peninsular Malaysia) were sequenced, assembled, and annotated using next-generation sequencing (NGS). A 16,465 bp and 16,470 bp length mitogenome sequence of P. nasutus and P. conchophilus, respectively, was generated, each containing 13 protein genes, 22 tRNAs, and two rRNAs, typical of most vertebrates. This is the first report of the complete mitochondrial genome sequences of P. nasutus and P. conchophilus. These data are a valuable genetic resource for future studies of these two commercially important species

Mitochondrial markers identify a genetic boundary of the Green Tiger Prawn (Penaeus semisulcatus) in the Indo-Pacific Ocean

A population genetics study of the commercially important Green Tiger Prawn (Penaeus semisulcatus) was conducted in the Indo-Pacific Ocean with a focus on the Indo-Malay Archipelago waters of the South China Sea (SCS), Sulu Sea (SLS), Celebes Sea (CLS) and the Strait of Malacca (SOM), the latter being the main waterway that connects the Indian Ocean with the Pacific Ocean. A 548-base-pair region of mitochondrial COI and 571 base pairs of the control region (CR) were analysed in 284 specimens from 15 locations. Genetic divergences (Tamura 3-parameter) for COI ranged from 0.1% to 7.2% and CR 2.3% to 21.7%, with Bagan Pasir (BGP) in central SOM being the most genetically different from other populations (COI: 3.3–4.2%; CR: 7.1–16.5%). All populations were differentiated into two lineages with a genetic break in the vicinity of BGP; Lineage I comprised populations south of this site (SCS, SLS, CLS and part of SOM) and Lineage II comprised populations north of BGP (part of the SOM). Specifically, most individuals of Bagan Pasir (BGP) and another site just south of it, Batu Pahat (BPT), clustered in Lineage I, while all SOM populations to the north of these sites clustered in Lineage II. The BGP population is believed to be a mixed gene pool between the two lineages. The results could be attributed to the fluctuations of Pleistocene sea levels and a possible influence of the One Fathom Bank in SOM. High genetic diversity was recorded, π (Lineage I: COI: 3.4%; CR: 7.4%) (Lineage II: COI: 3.8%; CR: 12.6%) and, h (Lineage I: COI: 0.81; CR: 1.0) (Lineage II: COI: 0.57; CR: 0.99). Demographic statistics revealed that both lineages underwent a sudden expansion and consequent stabilisation in genetic variability. The findings of this study have wide implications for fisheries in the Indo-Pacific. The increased sampling effort within a narrower geographical scale by the current study permitted a precise locality of the genetic break for this species within the Indo-Pacific Ocean to be identified. The substantial genetic diversity within both lineages should be considered in fishery management and aquaculture development programs of this species in this region