Evaluating potential alteration of genetic diversity in populations of redbreast sunfish (Lepomis auritus) using RAPD assay

Bioindicators of pollutant exposure can be more sensitive and ecologically relevant than simply measuring levels of pollutants in the environment and are applied here as tools for assessing stress on aquatic organisms. DNA polymorphisms, generated using the Randomly Amplified Polymorphic DNA (RAPD) technique, are used as biomarkers to assess genetic diversity and genetic distance among populations of redbreast sunfish (Lepomis auritus) residing in a contaminated stream (East Fork Poplar Creek – EFPC) and populations from reference streams. The RAPD technique uses the polymerase chain reaction (PCR) with short oligonucleotide primers under reduced stringency to produce DNA fragments which when analyzed by gel electrophoresis form banding patterns similar to DNA fingerprints. A total of 13 primers were used which produced forty- five polymorphic bands. Using the RAPD technique, genetic diversity and genetic distance were not found to be greatly different among populations within EFPC. No significant difference was seen between EFPC and the reference sites with respect to the genetic diversity of these populations. However, populations within EFPC were consistently less genetically distant from each other than they were from each of the reference sites. Differences in genetic distance between populations may be due to selection effects of EFPC pollutants. These data are discussed in relation to implications of RAPD assays, recent remediation efforts within EFPC, and future biomonitoring programs.