Genetic variability in meiotic gynogenetic muskellunge, Esox masquinongy (Mitchell), estimated from segregation of microsatellite alleles

Muskellunge, Esox masquinongy, is an important recreational freshwater fish native to North America. Since muskellunge populations are often maintained through stocking efforts, advances in muskellunge reproductive technologies are of direct relevance to fishery enhancement. We evaluated the efficiency of inbreeding through induced meiotic diploid gynogenesis. Eggs from six female muskellunge were manually stripped and activated using ultra violet-irradiated yellow perch, Perca flavescens, sperm. Hydrostatic pressure shocking regimes (48263kPa) were then applied to the eggs to prevent second polar body expulsion producing unambiguous meiotic gynogens. Six female dams and samples of 12-20 of their gynogenetic progeny were genotyped at seven polymorphic microsatellite loci. Chromosomal recombination frequencies of microsatellite loci based on retention of heterozygosity among gynogens ranged from 0.043 to 0.839 (0.576 +/- 0.237). There were no statistical differences in recombination frequency among females at any of the loci. The average inbreeding coefficient (F-value) ranged from 0.581 to 0.979, equivalent to three to fourteen generations of full-sibling crosses respectively. The average F-value overall was 0.712, equivalent to between five and six generations of full-sibling crosses. Centromere map distances of the seven microsatellite loci ranged from 2.15 to 41.95cM and meiotic gynogenesis was useful in eliminating heterozygosity at loci proximal to the centromere, but not distal. Since the age at maturity of female muskellunge is approximately 5years, gynogenesis may pose an expeditious alternative to traditional breeding strategies for creation of homozygous pedigrees for some loci that may be outcrossed to introduce positive heterozygosity effects in the offspring.