جستجوی مقالات مرتبط با کلیدواژه "نشانگر" در نشریات گروه "شیلات"

Regarding the importance of aquaculture industry development, it is necessary to focus on inbreeding in artificial propagation to prevent genetic diversity reduction and problems arising from low genetic variation. Indeed, lack of facilities and the rules related to the responsible transportation of live aquatic animals, and carelessness on health- diseases control in farms has led to some diseases outbreaks which have imposed high costs for farmers, including huge losses or cure. Therefore, it is required to identify the species and population traits before initiating any culturing or breeding programs and evaluate them with molecular genetic methods to synchronizing study with biological characteristics such as reproductive potential, growth rate, and mortality. Achieving broodstocks and fry owning genetically relatedness is a principal issue in each hatchery. This article tries to discuss the significance of genetic diversity assessment by microsatellite marker for broodstocks' genetic relatedness, with an emphasis on Asian sea bass.Keywords: diversity, pedigree, Asian sea bass, marker

Due to the lack of specified linage and parentage information from exotic broodstocks of Litopenaeus vannamei shrimp, in Iran, the status of genetic structure and genetic variability of this species isn’t clear. In order to estimate the current status of genetic pool and investigate the genetic variability indices, total of 30 samples from Amiri and Gorgeaj farms in Jask port of Hormozgan province, were detected with four microsatellite markers Pvan1758, TUDGLv1-3.224, TUDGLv5-7.33 & TUDGLv7-9.17. The number of alleles in every marker was 5-10; the mean number of alleles (Na) by populations ranged from 7.5 to 7.75 and their effective number of alleles (Ne) from 4.834 to 5.148. The mean value of observed heterozygosity (Ho) by populations ranged from 0.458 to 0.479, which was lower than the expected one (0.791-0.794). Observed heterozygosity values (Ho) were lower than expected heterozygosity values (He), except for TUDGLv1-3.224, in Gorgeaj population that indicating a general deficit of heterozygous types for the under studied markers. Mean polymorphism information content (PIC) in two populations based on markers (0.88), indicating the high polymorphism of studied markers. Amiri’s farm population in TUDGLv5-7.33 and Pvan1758 (P<0.001) markers; Gorgeaj’s farm population in TUDGLv5-7.33 (P<0.01), TUDGLv7-9.17 and Pvan1758 (P<0.001) markers; departed from Hardy-Weinberg equilibrium (HWE). The mean coefficient of inbreeding (FIS), 41%, and the coefficient of genetic differentiation among populations (FST), was 0.100. Using analysis of molecular variance (AMOVA), the molecular variability among (15%) and within (85%) populations were obtained. Also, values of PhiPT and Nm, 0.149 and 1.432 respectively, showed that there is moderate genetic differentiation and adequate gene flow among two studied populations. The high FIS and moderate FST highlight the importance of continuous evaluation of genetic variability in Hormozgan cultured Litopenaeus vannamei shrimp populations.

Rainbow trout, Oncorhynchus mykiss is the most important cold water farmed fish in Iran. Several cultivated stocks have been imported to Iran and some fish farms have focuesd on the culture and breeding of these stocks all around the country. In this study, the genetic structure of Spanish and American stocks of rainbow trout was investigated using 4 pairs of microsatellite markers and 30 specimens of fish from each stock. Allele sizes at OMY77, OMY325, OMM1329 and OMM1332 loci were in the range of 102-178, 100-150, 122-198, 172-204 bps respectively. Average number of observed alleles in American and Spanish stocks was 11 and 11.5, respectively. Average number of effective alleles in Spanish and American stock was 8.65 and 8.03, respectively. The mean of observed heterozygosity for American and Spanish stocks were calculated as 0.59 and 0.63, respectively. The mean of expected heterozygosity for both stocks was very similar (around 0.86). The results showed a significant deviation from Hardy-Weinberg equilibrium at seven out of eight loci × stock. AMOVA test showed low (7%) genetic diversity between stocks, while the most (93%) genetic diversity was observed within stocks. Genetic identity and genetic distance between stocks were 0.831 and 0.186, respectively. Fixation index FST was calculated based on allelic frequency between two stocks was 0.012 with no significant difference between 2 stocks. The results of this study showed that while there was considerable genetic diversity within Spanish and American stocks, two stocks were very similar and showed very insignificant genetic differentiation based on 4 microsatellite studied loci.