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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