title: Natural Variation in Fish Transcriptomes: Comparative Analysis of the Fathead Minnow (Pimephales promelas) and Zebrafish (Danio rerio).
abstract: Fathead minnow and zebrafish are among the most intensively studied fish species in environmental toxicogenomics. To aid the assessment and interpretation of subtle transcriptomic effects from treatment conditions of interest, better characterization and understanding are needed for natural variation in gene expression among fish individuals from lab cultures. Leveraging the transcriptomics data from a number of our toxicogenomics studies conducted over the years, we conducted a meta-analysis of nearly 600 microarrays generated from the ovary tissue of untreated, reproductively mature fathead minnow and zebrafish samples. As expected, there was considerable batch-to-batch transcriptomic variation; this "batch-effect" appeared to differentially impact subsets of fish transcriptomes in a nonsystematic way. Temporally more closely spaced batches tended to share a greater transcriptomic similarity among one another. The overall level of within-batch variation was quite low in fish ovary tissue, making it a suitable system for studying chemical stressors with subtle biological effects. The observed differences in the within-batch variability of gene expression, at the levels of both individual genes and pathways, were probably both technical and biological. This suggests that biological interpretation and prioritization of genes and pathways targeted by experimental conditions should take into account both their intrinsic variability and the size of induced transcriptional changes. There was significant conservation of both the genomes and transcriptomes between fathead minnow and zebrafish. The high degree of conservation offers promising opportunities in not only studying fish molecular responses to environmental stressors by a comparative biology approach, but also effective sharing of a large amount of existing public transcriptomics data for developing toxicogenomics applications.
authors.affiliation: Ecological Exposure Research Division, National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, Ohio, United States of America; Mid-Continent Ecology Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Duluth, Minnesota, United States of America.
authors.forename: Rong-Lin
authors.initials: RL
authors.lastname: Wang
authors.affiliation: Ecological Exposure Research Division, National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, Ohio, United States of America.
authors.forename: David C
authors.initials: DC
authors.lastname: Bencic
authors.affiliation: Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Starkville, Mississippi, United States of America.
authors.forename: Natàlia
authors.initials: N
authors.lastname: Garcia-Reyero
authors.affiliation: Environmental Laboratory, US Army Engineer Research and Development Center, US Army Corps of Engineers, Vicksburg, Mississippi, United States of America.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Perkins
authors.affiliation: Mid-Continent Ecology Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Duluth, Minnesota, United States of America.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Villeneuve
authors.affiliation: Mid-Continent Ecology Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Duluth, Minnesota, United States of America.
authors.forename: Gerald T
authors.initials: GT
authors.lastname: Ankley
authors.affiliation: Ecological Exposure Research Division, National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, Ohio, United States of America.
authors.forename: Adam D
authors.initials: AD
authors.lastname: Biales
mesh_terms: D000818:Animals; D003530:Cyprinidae / Q000235:genetics*; D014644:Genetic Variation; D020411:Oligonucleotide Array Sequence Analysis; D059467:Transcriptome; D015027:Zebrafish / Q000235:genetics*