No abstract

Solenocera crassicornis is a commercially important shrimp of the Solenoceridae family. The current study investigated the morphology, molecular identification, phylogenetic relationships, and population dynamics of S. crassicornis in Egypt. Samples were collected monthly (total, 1722; male = 40.19%, wet weight, 0.89–10.77 g; female = 59.81%, wet weight, 1.55–19.24 g) from Al-Attaka commercial catch in the Gulf of Suez in the Red Sea. Two barcode markers, 18S rRNA and cytochrome c oxidase subunit I (COI), were used for molecular identification. COI partial sequences were used to construct the phylogenetic relationships among different species of genus Solenocera and to infer the origin of the studied Solenocera crassicornis. The applied molecular markers successfully identified the studied species to the species level. The genetic distances among S. crassicornis sequences from different countries revealed the Indo-West Pacific origin of S. crassicornis. The relationship between total length (TL) and total weight (TW) was TW = 0.035TL2.275 and r2 = 0.805 for males and TW = 0.007TL3.036 and r2 = 0.883 for females, indicating that females were heavier than males. Despite its social and economic relevance in the area, information on the hatching, larval rearing, and farming of S. crassicornis is scarce and requires future studies under Egyptian conditions.

No abstract

DNA barcoding is one of the powerful DNA-based identification tools that are used for accurate identification of a species. Despite several DNA barcodes were used, the accuracy and suitability of these barcodes depend on speciesspecific variations.The current study was conducted to compare the efficiency of two mitochondrial genes to the nuclear Internal Transcribed Spacer (ITS) region in the molecular identification of genus Dicentrarchus. A total of 80 fish samples for Dicentrarchus labrax and Dicentrarchus punctatus were randomly collected from two different locations in Egypt; Alexandria and Bardawil Lagoon. All samples were morphologically characterized. For species barcoding, the ITS region was firstly employed to carry out the PCR amplifications. Additionally, two mitochondrial genes; cytochrome b (Cyt b) and cytochrome oxidase subunit I (COI) were also used for species barcoding. To evaluate the efficiency of each marker, three different approaches were used. Firstly, phylogenetic relationship was constructed between the collected samples and a reference species using each genetic marker. Secondly, Automated Barcode Gap Discovery (ABGD) method was used for each marker in order to assign the samples into presumed species without priori species assumption. Lastly, the Poisson Tree Processes (PTP) model was used which relies on Bayesian support values to delimit species on the input tree. The two species of genus Dicentrarchus exhibited nearly similar ITS sequences, leading to an ambiguous identification of the two species. However, the two mitochondrial COI and Cyt b genes were able to accurately distinguish between the two species. The three approaches, phylogeny, ABGD and PTP presented consistent results. Overall, COI and Cyt b outperformed ITS in assigning species accurately. Mitochondrial barcodes could provide a leading guide for fish species identification. ITS should be abandoned in favor of COI and Cyt b as primary DNA barcode markers for fish species in general and Dicentrarchus genus, in particular.

No abstract