Microsatellite DNA markers reveal new levels of genetic variation in northern pike

Using single-locus microsatellite markers, higher levels of genetic variation were resolved than previously reported for northern pike (Esox lucius). 14 (AC)n.(TG)n microsatellite loci were isolated from a genomic library of northern pike. Primer pairs for the polymerase chain reaction were developed for 9 of the loci and used to assess genetic variation using fish scales as the source of DNA. In 4 populations, 4 polymorphic loci with 3 or 4 alleles at each locus were found. Average heterozygosity at all loci was 0.075. Although this level of genetic variation is the highest reported for this species, it is much lower than that found for many other fish species using microsatellite markers. Small numbers of founder fish, combined with loss of variation due to genetic drift in the small populations typical of northern pike, may explain the relatively low levels of genetic variation..