Assessment of genetic diversity of fish and rotifers in the Rio Grande: A biomarker of anthropogenic stress

Guadalupe Garbalena, University of Texas at El Paso


The Rio Grande is a heavily populated and industrialized river in which numerous contaminants have been identified. Although water and sediment quality are monitored by government agencies, little is known on how anthropogenic stressors in the Rio Grande affect its aquatic life. Thus, the goals of this thesis were to evaluate the integrity of the river's aquatic ecosystem by assessing gene diversity in sentinel species, and to help establish the measure of genetic diversity as a useful biomarker. The study was conducted at a reference site (Williamsburg) and three experimental sites (Anthony, Montoya Drain, and Fort Hancock). Two fish (carp, Cyprinus carpio and shad, Dorosoma cepedianum) and rotifer species (Plationus patulus, Euchlanis dilatata) were studied. DNA was extracted from individuals, and amplified fragment length polymorphism (AFLP) was used to create DNA profiles for each fish and rotifer population across the four sites. General water chemistry was also done at each site. PCR products from the AFLP reactions were run on an automated sequencer and analyzed using GeneImagIR (LICOR). By constructing matrices based on the presence and absence of DNA bands, clustering analysis, genetic distance, and measures of genetic diversity (average heterozygosity, percent polymorphism, genetic diversity, fixation indices) were calculated for each species across all sites. Using an AMOVA, it was found that D. cepedianum and E. dilatata both exhibited statistically significant decreases in genetic diversity as we moved downstream, while C. carpio and P. patulus showed increases.

Subject Area

Molecular biology|Ecology|Genetics|Aquaculture|Fish production

Recommended Citation

Garbalena, Guadalupe, "Assessment of genetic diversity of fish and rotifers in the Rio Grande: A biomarker of anthropogenic stress" (2005). ETD Collection for University of Texas, El Paso. AAI1430938.