title: Genetic and life-history trait variation of the amphipod Melita plumulosa from polluted and unpolluted waterways in eastern Australia.
abstract: To monitor genetic diversity and environmental contamination in eastern Australia, toxicity studies have employed the sensitive benthic amphipod Melita plumulosa. The goal of this study was to examine the genetic and life-history variability of natural populations of M. plumulosa from the Parramatta (polluted) and Hawkesbury (unpolluted) Rivers. The underlying genetics of the populations in these distinct waterways was examined at one mitochondrial (cytochrome c oxidase subunit I (COI)) and one nuclear (ribosomal internal transcribed spacer region 1 (ITS1)) locus. Seven unique haplotypes for COI were found amongst animals from the Parramatta River, while animals from the Hawkesbury River showed a complete absence of genetic variation at this locus. At ITS1 a total of two sequence variants were found amongst Parramatta River amphipods and three sequence variants among Hawkesbury River animals, with no common variants across the two river systems. To establish whether genetic differences were associated with organismal responses to toxicant exposure, two life-history trait variables (female head length as an estimator of amphipod size and female fecundity) were analyzed. Life-history trait analyses showed that females from the Hawkesbury River were significantly larger and more fecund. These data have critical implications for toxicity tests, the use of laboratory cultures for testing purposes, and environmental contamination in Sydney Harbor.
authors.affiliation: Evolution and Ecology Research Centre, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney 2052, Australia.
authors.forename: Pann Pann
authors.initials: PP
authors.lastname: Chung
authors.forename: Ross V
authors.initials: RV
authors.lastname: Hyne
authors.forename: Reinier M
authors.initials: RM
authors.lastname: Mann
authors.forename: J William O
authors.initials: JW
authors.lastname: Ballard
mesh_terms: D033304:Amphipoda / Q000502:physiology*; D000818:Animals; D001315:Australia; D002467:Cell Nucleus / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism; D004784:Environmental Monitoring; D005260:Female; D005298:Fertility / Q000235:genetics; D005618:Fresh Water / Q000032:analysis*; D014644:Genetic Variation; D006257:Head / Q000033:anatomy & histology; D008018:Life Cycle Stages / Q000502:physiology*; D008928:Mitochondria / Q000201:enzymology; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014876:Water Pollution
chemical_list: D004272:DNA, Mitochondrial; D021903:DNA, Ribosomal Spacer; D014874:Water Pollutants, Chemical; D003576:Electron Transport Complex IV