Originally published as Genetics Published Articles Ahead of Print on September 14, 2008.

Genetics, Vol. 180, 1233-1243, October 2008, Copyright © 2008
doi:10.1534/genetics.108.089144

Metabolomic Signatures of Inbreeding at Benign and Stressful Temperatures in Drosophila melanogaster

* Aarhus Centre for Environmental Stress Research, Department of Biological Sciences, University of Aarhus, DK-8000 Aarhus C, Denmark, {dagger} Department of Genetics and Biotechnology, University of Aarhus, DK-8830 Tjele, Denmark, {ddagger} Carlsberg Laboratory, Gamle Carlsberg Vej 10, DK-2500 Valby, Denmark and § Center for Insoluble Protein Structures, Interdisciplinary Nanoscience Center, and Department of Chemistry, University of Aarhus, DK-8000 Aarhus C, Denmark

2 Corresponding author: Department of Chemistry, University of Aarhus, Langelandsgade 140, DK-8000 Aarhus C, Denmark.
E-mail: anders{at}chem.au.dk

While the population genetics of inbreeding is fairly well understood, the effects of inbreeding on the physiological and biochemical levels are not. Here we have investigated the effects of inbreeding on the Drosophila melanogaster metabolome. Metabolite fingerprints in males from five outbred and five inbred lines were studied by nuclear magnetic resonance spectroscopy after exposure to benign temperature, heat stress, or cold stress. In both the absence and the presence of temperature stress, metabolite levels were significantly different among inbred and outbred lines. The major effect of inbreeding was increased levels of maltose and decreased levels of 3-hydroxykynurenine and a galactoside [1-O-(4-O-(2-aminoethyl phosphate)-β-D-galactopyranosyl)-x-glycerol] synthesized exclusively in the paragonial glands of Drosophila species, including D. melanogaster. The metabolomic effect of inbreeding at the benign temperature was related to gene expression data from the same inbred and outbred lines. Both gene expression and metabolite data indicate that fundamental metabolic processes are changed or modified by inbreeding. Apart from affecting mean metabolite levels, inbreeding led to an increased between-line variation in metabolite profiles compared to outbred lines. In contrast to previous observations revealing interactions between inbreeding and environmental stress on gene expression patterns and life-history traits, the effect of inbreeding on the metabolite profile was similar across the different temperature treatments.