Submitted to: Mote International Symposium on Marine Stock Enhancement: A New Perspective
Publication Type: Abstract Only
Publication Acceptance Date: 11/15/1996
Publication Date: N/A
Citation: N/A Interpretive Summary:
Technical Abstract: Analysis of genetic diversity in wild and natural populations, contributions and impacts of hatchery stocks on natural populations, and changes in genetic structure are important considerations in stock enhancement programs. Methods for estimating the genetic structures of fish populations utilizing electrophoresis of protein, and mitochondrial and nuclear DNA (multilocus fingerprinting) have limitations. Microsatellites, molecular genetic markers based on tandem-repeat DNA sequences, are more useful than isozyme loci for genetic analyses of fish populations because alleles are more polymorphic, gene expression is not necessary, small amounts of DNA from non-invasive tissues are required, and analysis is rapid using PCR techniques. Microsatellite markers can be used to measure levels of heterozygosity at hundreds of loci in populations, identify individual fish in stock enhancement programs, and measure contributions of genes from hatchery stocks into wild populations. Allelic heterozygosity was measured in wild and domestic channel catfish, Ictalurus punctatus, populations using microsatellite loci. For example, a wild population from the Mississippi River contained 12 alleles at locus Ip001 with 86% average heterozygosity, while a hatchery population in a selective breeding program contained 8 alleles at the same locus with 89% average heterozygosity. Measurement of genetic variation from microsatellite loci, and the ability to genetically identify different individuals at high resolution, allows direct evaluation of enhancement effects and gene flow from hatchery stocks into wild populations. High resolution analysis may also redefine genetic diversity.