Genetic Variation and Postglacial Dispersal of Populations of Northern Pike (Esox lucius) in North America

Abstract

We studied the genetic relationships and postglacial dispersal of northern pike (Esox lucius) populations in North America using allozyme data. Allelic products of up to 65 protein coding loci were examined in eight populations: five from drainages in western Canada, flowing into Hudson Bay and the Beaufort Sea; two from the Missouri River drainage, flowing into the Mississippi River; and one from the upper Mississippi River drainage, flowing into the Gulf of Mexico. Only two polymorphic loci were identified, Est-1 and Ck-1, and the average observed heterozygosity was only 0.001, much lower than that observed in most teleosts. All of the populations from the drainages in western Canada and the Missouri River were genetically identical. The Mississippi River population was unique, expressing Ck-1 (140), an allele nearly absent in all other populations, at a frequency of 0.99. Our data suggest that the Missouri River drainage, during the period when it was isolated from the Mississippi River, was the southern refugium from which northern pike radiated during deglaciation.