Sequenced genomes often contain some fraction of genes with unknown functions, even among the most well-studied genetic model species for biomedical research, such as the fruit fly Drosophila. By using microarrays (containing millions of DNA strands affixed to microscope slides) that are made to measure the conditions under which these new genes are transcribed into precursors for proteins, experiments that subjected Daphnia to environmental stressors point to these unknown genes having ecologically significant functions.
"If such large fractions of genomes evolved to cope with environmental challenges, information from traditional model species used only in laboratory studies may be insufficient to discover the roles for a considerable number of animal genes," Colbourne said.
Daphnia is emerging as a model organism for a new field of science -- Environmental Genomics -- that aims to better understand how the environment and genes interact. This includes a practical need to apply scientific developments from this field toward managing our water resources and protecting human health from chemical pollutants in the environment.
James E. Klaunig, professor and chair of the School of Health, Physical Education, and Recreation's Department of Environmental Health at IU Bloomington, predicts the present work will yield a more realistic and scientifically-based risk evaluation.
"Genome research on the responses of animals to stress has important implications for assessing environmental risks to humans," Klaunig said. "The Daphnia system is an exquisite aquatic sensor, a potential high-tech and modern version of the mineshaft canary. With knowledge of its genome, and using both field sampling and laboratory studies, the possible effects of environmental agents on cellular and molecular pr
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