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Cytochrome b sequences in black-crowned night-herons (Nycticorax nycticorax) from heronries exposed to genotoxic contaminants

Dahl, C. R., Bickham, J. W., Wickliffe, J. K., and Custer, T. W., 2001, Cytochrome b sequences in black-crowned night-herons (Nycticorax nycticorax) from heronries exposed to genotoxic contaminants: Ecotoxicology, v. 10, no. 5, p. 291-296. 89-100.

Abstract

DNA sequence analysis of a 215 base-pair region of the mitochondrial cytochrome b gene was used to examine genetic variation and search for evidence of an increased mutation rate in black-crowned night-herons. We examined five populations exposed to environmental contamination (primarily PAHs and PCBs) and one reference population from the eastern U.S. There was no evidence of a high mutation rate even within populations previously shown to exhibit increased variation in DNA content among somatic cells as a result of petroleum exposure. Three haplotypes were observed among 99 individuals. The low level of variability could be evidence for a genetic bottleneck, or that cytochrome b is too conservative for use in population genetic studies of this species. With the exception of one population from Louisiana, pair-wise Phi(st) estimates were very low, indicative of little population structure and potentially high rates of effective migration among populations.

Keywords: mitochondrial DNA, population genetics, environmental contamination, DNA sequencing, cytochrome b, black-crowned night-herons, Nycticorax nycticorax, population genetic-structure, mitochondrial-DNA, natural-populations, restriction data, crude-oil, ecotoxicology, diversity, evolution, chernobyl, mutations