SREL Reprint #0824




Biochemical Genetics of Mosquitofish.

Environmental Correlates, and Temporal and Spatial Heterogeneity of Allele Frequencies within a River Drainage

Michael W. Smith, Michael H. Smith and Ronald K. Chesser



Seventy mosquitofish populations within the Savannah River drainage were surveyed for biochemical variation of proteins encoded by six loci.  Consistent excesses or deficiencies of heterozygotes were not observed for any of the six loci, although strong spatial variation existed among populations within and between creeks and reservoirs or within the river.  Heterozygosities of the river populations varied as function of the distance from the first dam form the mouth of the river.  Two of six populations which had been sampled in a previous study several years before this one showed significant changes in allele frequencies.  Differences in allele frequencies were related to major environmental categories, such as water temperature, flow characteristics and elevation of the site.  These observations are not consistent with the neutrality model but suggest a genetically dynamic species subjected to both selection and stochastic processes as described in the shifting balance model of evolution.


SREL Reprint #0824

Smith, M.W., M.H. Smith, and R.K. Chesser. 1983. Biochemical genetics of mosquitofish. I. Environmental correlates, and temporal and spatial heterogeneity of allele frequencies within a river drainage. Copeia 1983:182-193.

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