Microsatellites reveal weak genetic differentiation between Rutilus frisii kutum (Kamenskii, 1901) populations south of the Caspian Sea

Abstract

Rutilus frisii kutum (Kamenskii, 1901) is one of the most important bony fish inhabiting the Caspian Sea. The Iranian Fisheries Organization produced up to 200 million fry to restock the Caspian Sea population annually. Loss of genetic stocks and gradual depletion of the gene pool are parameters of great concern for the future of the species. In the present study, we used ten microsatellite markers to estimate the level of genetic diversity and compare the degree of genetic differentiation among kutum populations collected from Gharesou, Tajan and Goharbaran rivers in the south of Caspian Sea. The average number of alleles per locus ranged from 4 to 12.33, while the average observed and expected heterozygosity ranged from 0.22 to 1.00 and from 0.69 to 0.88, respectively. Through AMOVA, a low level of variation between regions as well as a large percentage of total variation within population was observed. Current knowledge about artificial breeding suggests that offspring transfer between rivers has probably reduced the natural divergence naturally exists between these pools. These results could be useful for the genetic management of kutum populations.

Untitled

“…In addition to the mentioned possible reasons, microsatellites are more efficient to detect genetic variation in species than RFLP (Shaw, Turan, Wright, O'Connell, &Carvalho, 1999), which may explain the lower concordance among the RFLP data and our results. However, our results were in accordance to the study by Rezaei et al (2011) who reported the number of alleles, expected and observed heterozygosity 8.29, 0.793 and 0.766, respectively for three wild populations (Goharbaran, Tajan and Qaresou) of Caspian kutum using the same microsatellite loci. While the observed and expected heterozygosity noticed in the present study were higher than those reported in 13 other freshwater (H O : 0.46 and H E : 0.54) and 7 anadromous species (H O and H E : 0.68), the mean number of alleles was lower than that of freshwater and anadromous fishes (9.1 and 10.8, respectively) (DeWoody&Avise, 2000).…”

“…However, as reported by Balloux and Lugon-Moulin (2002), even this low level of F ST may indicate important genetic differentiation. The low F ST value was previously detected between the other wild populations of R. kutum (Rezaei et al, 2011) whereas Rezvani-Gilkolaei et al (2012) reported a moderate level of genetic differentiation between the southwest populations of Caspian kutum, possibly related to the difference in geographical localities of sampling. Sefc, Payne, and Sorenson (2007) demonstrated that because of greater variance, R ST is less dependable for detecting differentiation than F ST .…”

“…10pairs of microsatellite primers, CypG3, CypG24, CypG27, CypG30 (Baerwald& May, 2004), Rru2, Rru4, Lid1 (Barinova, Yadrenkina, Nakajima, & Taniguchi, 2004), Z21908 (ZFIN, 2003, Ca1 and Ca3 (Dimsoski, Toth, & Bagley, 2000) (Table 1),were selected to investigate the genetic diversity between R. kutum populations based on the studies by Hamilton and Tayler (2008)and Rezaei et al (2011).PCR reactions were performed using a thermal cycler system (Bio-RAD MJ Mini Thermal Cycler, USA) with a reaction volume of 12.5 μl. The thermal cycling conditions were as follows: 3 min at 94 0 C, followed by 35 cycles of 30 s at the annealing temperatures given in Table 1, 1 min at 72 0 C and 3 min at 72 0 C (Rezaei et al, 2011).…”

“…The thermal cycling conditions were as follows: 3 min at 94 0 C, followed by 35 cycles of 30 s at the annealing temperatures given in Table 1, 1 min at 72 0 C and 3 min at 72 0 C (Rezaei et al, 2011). The PCR products were separated using electrophoresis in 10% polyacrilamide gel for 4 h. The gels were stained using silver nitrate method (Benbouza, Jacquemin, Baudoin, &Mergeai, 2006) and visualized under UV light on a gel documentation system (Gel Doc XR, Bio-Rad, USA).The length of microsatellite alleles was determined by Gel Pro Analyzer 3.9 software.…”

“…Unfortunately, despite that restocking programs have been widely implemented for R. kutum populations during recent years, there is no molecular information on the hatchery-produced populations of Caspian kutum. However, there are few studies on the wild populations of R. kutum in some regions of the Caspian Sea (Rezaei, Shabani, Shabanpour, &Kashiri, 2011;Abdolhayet al, 2012;Rezvani Gilkolaei, Kavan, & Safari, 2012).…”