الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
Background and aims: Fishes are the main animal protein source for human beings and play a vital role in aquatic ecosystems and food webs. Fish identification can be challenging, especially in the tropics (due to high diversity), and this is particularly true for larval forms or fragmentary remains. DNA barcoding, which uses the 5′ region of the mitochondrial cytochrome c oxidase subunit I (COI) as a target gene, is an efficient method for standardized species-level identification for biodiversity assessment and conservation, pending the establishment of reference sequence libraries.
Materials and methods: In this study, fishes were collected from the Meditternean Sea, identified morphologically, and imaged digitally. DNA was extracted, PCR-amplified, and the standard barcode region was bidirectionally sequenced for 27 species in 16 families. All specimen provenance data and associated sequence information were recorded in the barcode of life data systems (BOLD; www.barcodinglife.org). Analytical tools on BOLD were used to assess the performance of barcoding to identify species.
Results: The studyemphasized the distinguishing power of COI barcodes and the effectiveness of applying them inconditions entailing determination of species beginning with query sequences. A total of 54 DNAbarcodes utilizing a 680 bp-long portion of the mitochondrial cytochrome oxidase subunit I (COI) gene was derived from 27 species representing 15 families. The average genetic divergencecalculated via Kimura two parameter model between families was 0.243. The percent GC contentdiffered between species and ranged between 40.80% in Coryphaena hippurus and 51.20% inSaurida undosquamis. The Neighbor Joining tree revealed obvious gathering of the 27 fishspecies presented in two clustering groups. The related species appeared in the same group andwithin each group, deeply related species appear on the same clade. Meanwhile, unrelated specieswere spread apart. Results of the present study prove that COI barcode successfully helped inidentifying some Mediterranean Sea fish species. Findings verify the significance of referencelibraries of authenticity grade-glossed DNA barcodes, in identifying species from variousenvironmental origins. The capacity to identify species with great accuracy from DNA samples ofdifferent quality and origin has a great significance in numerous domains, such as fisheries,preservation programs and controlling fish products validity.Keywords: DNA barcoding, cytochrome oxidase subunit one gene (COI), Mediterranean Sea.