Molecular and biochemical genetic analysis of stur

• Main Author: Pourkazemi, M.
• Published: Swansea University 1995
• Subjects: 591.7
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638222

The stock structure of two sturgeon species from the South Caspian Sea was investigated. Allozyme electrophoresis and PCR-based mDNA analysis (RFLP) was used for the study of population differentiation in the stellate sturgeon (<I>Acipenser stellatus</I>). The allozyme study revealed a high level of polymorphism both within and between populations. The overall average heterozygosity is estimated to be 0.108 ± 0.02 and the percentage of polymorphic loci to be 64.3%. No significant differences in allele frequencies were observed in comparisons between the four geographic regions studied. The mDNA ND 5/6 gene regions were amplified using PCR techniques followed by RFLP analysis. Nine different composite haplotypes were detected among 120 specimens. The average nucleotide and haplotype diversity within populations are estimated to be 0.009 ± 0.001 and 0.4322 ± 0.002 respectively. No significant differences in the distribution of haplotypes were observed either within or between populations. The population structure of the Russian sturgeon (<I>Acipsenr güeldenstaedti</I>) was investigated using PCR amplification of the mtDNA D-loop region. Seven composite haplotypes were detected and average nucleotide and haplotype diversity over all populations were found to be 0.05 ± 0.00 and 0.75 ± 0.00 (mean ± SE) respectively. Restriction digest of the mtDNA D-loop region detected two genotypes A and B with relative high frequencies of 0.5 and 0.36 respectively. A maximum of 10.8% nucleotide diversity was found between haplotypes AAAAB and BBBBF. These two genotypes (A and B) can be considered as potential genetic markers for different biological groups, stocks or seasonal races of Russian sturgeon. 100% heteroplasmy was found in Russian sturgeon and restriction digest of the mtDNA D-loop region also exhibited site heteroplasmy. PCR amplification, cloning and sequence analysis of the entire mtDNA D-loop region indicates that all five sturgeon species in the South Caspian Sea show heteroplasmy. In all five species length heteroplasmy is associated with the presence of an 82 bp sequence which is tandemly repeated in the mtDNA D-loop region.