title: Comparison of histological, genetic, metabolomics, and lipid-based methods for sex determination in marine mussels.
abstract: Omics technologies are increasingly being used to monitor organismal responses to environmental stressors. Previous studies have shown that species identification, an appreciation of life history traits, and organism phenotype (e.g., gender) are essential for the accurate interpretation of omics data from field samples. As marine mussels are increasingly being used in ecotoxicogenomics and monitoring, a technique to determine mussel gender throughout their annual reproductive cycle is urgently needed. This study examines four methods for sex determination in the two mussel species found in the United Kingdom, Mytilus edulis and Mytilus galloprovincialis, and their hybrid. Each of these methods-histology, a lipid-based assay, a new reverse transcriptase polymerase chain reaction (RT-PCR) assay, and nuclear magnetic resonance (NMR)-based metabolomics-initially was evaluated using sexually mature ("ripe") mussels whose gender was clearly distinguishable using histology. The methods subsequently were tested on spawned ("spent") mussels. For ripe animals, all techniques yielded high classification accuracies: histology, 100%; RT-PCR, 94.6%; lipid analysis, 90.6%; and metabolomics, 89.5%. The gender of spent animals, however, could not be determined by histology (0%) or lipid analysis (55.6%), but RT-PCR (100%) and metabolomics (88.9%) both proved to be successful. In addition, the RT-PCR, metabolomics, and lipid-based methods identified animals of mixed sex. Our findings highlight the application of a novel RT-PCR method as a robust technique for gender determination of ripe and spent mussels.
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: Adam
authors.initials: A
authors.lastname: Hines
authors.forename: Wai Ho
authors.initials: WH
authors.lastname: Yeung
authors.forename: John
authors.initials: J
authors.lastname: Craft
authors.forename: Margaret
authors.initials: M
authors.lastname: Brown
authors.forename: Jill
authors.initials: J
authors.lastname: Kennedy
authors.forename: John
authors.initials: J
authors.lastname: Bignell
authors.forename: Grant D
authors.initials: GD
authors.lastname: Stentiford
authors.forename: Mark R
authors.initials: MR
authors.lastname: Viant
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods*; D049872:Bivalvia / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D008055:Lipids / Q000032:analysis*; D008853:Microscopy; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012732:Sex Determination Analysis / Q000379:methods*
chemical_list: D008055:Lipids