SREL Reprint #2143
Cytonuclear introgressive swamping and species turnover of bass after an introduction
J. C. Avise1, P. C. Pierce2, M. J. Van Den Avyle3, M. H. Smith4,5, W. S. Nelson1, and M. A. Asmussen1
1Department of Genetics, University of Georgia, Athens, GA 30602
2Georgia Cooperative Fish and Wildlife Research Unit
3National Biological Service
4Daniel B. Warnell School of Forest Resources, University of Georgia, Athens, Georgia
5Savannah River Ecology Laboratory, Aiken, South Carolina
Abstract: Species-specific RFLP markers from mitochondrial DNA (mtDNA) were identified and employed in conjunction with previously reported data for nuclear allozyme markers to examine the genetic consequences of an artificial introduction of spotted bass (Micropterus punctulatus) into a north Georgia reservoir originally occupied by native smallmouth bass (M. dolomieui). The cytonuclear genetic data indicate that within 10-15 years following the unauthorized introduction, a reversal in these species' abundances has occurred and that more than 99% of the population sample analyzed here consists of spotted bass or products of interspecific hybridization. This demographic shift, perhaps ecologically or environmentally mediated, has been accompanied by introgressive swamping; more than 95% of the remaining smallmouth bass nuclear and cytoplasmic alleles are present in individuals of hybrid ancestry. Dilocus cytonuclear disequilibria were significantly different from zero, with patterns indicative of an excess of homospecific genetic combinations (relative to expectations from single-locus allelic frequencies) and a disproportionate contribution of smallmouth bass mothers to the hybrid gene pool. Results document dramatic genetic and demographic changes following the human-mediated introduction of a normative species.
SREL Reprint #2143
Avise, J.C., P.C. Pierce, M.J. Van Den Avyle, M.H. Smith, W.S. Nelson, and M.A. Asmussen. 1997. Cytonuclear introgressive swamping and species turnover of bass after an introduction. Journal of Heredity 88:14-20.
This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).