Mitochondrial DNA variation in wild and hatchery populations of northern pike, Esox lucius L.

Esox lucius is an economically important freshwater species. Mitochondrial cytb, 12SrRNA, and 16SrRNA gene sequences were used in order to clarify the genetic variation and population structure in three E. lucius populations, i.e., one Wild population (W) and two hatchery populations (Hatchery Population I-HPI and Hatchery Population II-HPII). A total of 55 individuals, with 19 from wild and 18 from each hatchery population, were sequenced. The results are as follows: 1) cytb. Eleven variable sites defined eight distinct haplotypes, with 1137 base pairs (bp) complete cytb sequences. The nucleotide diversity (π) values were W 0.009%, HPI 0.075% and HPII 0.068%, respectively. Genetic distances within and between populations were both between 0 and 0.1%. Analysis of molecular variance (AMOVA) analysis revealed that variation within populations accounts for 98.49% of total variation. 2) 12SrRNA. We obtained 380 bp consensus 12SrRNA sequence and found little variation among the 55 sequences. 3) 16SrRNA. Twelve variable sites defined seven haplotypes, with 519 bp consensus 16SrRNA sequence. The π values were W 0.041%, HPI 0.310% and HPII 0.021%, respectively. Genetic distances were between 0 and 0.3% within populations and from 0 to 0.2% between populations. AMOVA disclosed that variation within populations accounts for 91.79% of total variation. Variation within populations is the main source of total variation. The results suggest that low genetic variation can be found in both wild and hatchery populations of E. lucius, and the effect of genetic drift and adaptation to culture conditions gradually emerged under only two generations’ artificial cultivation