احمد شادی

Objective: In the present study, we employed sequencing of COI gene to achieve basic genetic information on previously identified Sillaginid fish as Sillago sihama in the north Persian Gulf. Methods: In the present study, ten specimens were collected from two sampling sites in the North Persian Gulf ( Bushehr and Hormozgan provinces) and then were morphologically and biometrically analysed. Meristic counts and morphometric traits including body length, fin length, were determined by Imagej software and analysed using Excel and SPSS softwares. In order to study the phylogenetic relations of Sillaginidae family in the region, COI sequencing methodology was used. Universal primers of FISH F1 and FISH R1 were used for PCR amplification. After sequencing, data was analyzed using Chromas ver. 2.33, BioEdit ver 7.0, MEGA ver 5 and DNAsp ver 5.10. Results and Discussion: No significant morphological differences was detected between samples, however the genetic analysis results, showed high heterogeneity of specimens. According to analysed phylogenetic relationships of the COI sequences, the present study dose not support previous identification of Sillago sihama in the region, and samleswere divided into 3 groups (potential cryptic species) and genetic statistics were calculated separately for these groups. Haplotype diversity in groups 1, 2 and 3 was high and estimated 1, 1, and 0.95 respectively The genetic distance of 0.225, 0.226 and 0.20 amongst three groups were in the range of different species of the same genus. The results confirm high genetic differentiation, which enhances the possibility of different Sillaginids species or subspecies. The results of the present study do not confirm previous identification of north Persian Gulf Sillaginids (Sillago sihama) and suggest the presence of a Sillago complex in Persian Gulf which are not morphologically easily identifiable. It is recommended, however, other genetic markers and microscopic examination also be used to com