Evidence for evolutionary constraints in Drosophila metal biology Maryam Sadraie • Fanis Missirlis Received: 13 December 2010 / Accepted: 24 January 2011 / Published online: 4 February 2011 Ó Springer Science+Business Media, LLC. 2011 Abstract Mutations in single Drosophila melano- gaster genes can alter total body metal accumulation. We therefore asked whether evolutionary constraints maintain biologically abundant metal ions (iron, copper, manganese and zinc) to similar concentra- tions in different species of Drosophilidae, or whether metal homeostasis is a highly adaptable trait as shown previously for triglyceride and glycogen storage. To avoid dietary influences, only species able to grow and reproduce on a standard laboratory medium were selected for analysis. Flame atomic absorption spectrometry was used to determine metal content in 5-days-old adult flies. Overall, the data suggest that the metallome of the nine species tested is well conserved. Meaningful average values for the Drosophilidae family are presented. Few statistically significant differences were noted for copper, man- ganese and zinc between species. In contrast, Dro- sophila erecta and Drosophila virilis showed a 50% increase above average and a 30% decrease below average in iron concentrations, respectively. The changes in total body iron content correlated with altered iron storage in intestinal ferritin stores of these species. Hence, the variability in iron content could be accounted for by a corresponding adaptation in iron storage regulation. We suggest that the relative expression of the multitude of metalloen- zymes and other metal-binding proteins remains overall similar between species and likely determines relative metal abundances in the organism. The availability of a complete and annotated genome sequence of different Drosophila species presents opportunities to study the evolution of metal homeo- stasis in closely related organisms that have evolved separately for millions or dozens of million years. Keywords Transition metals Á Insect physiology Á Ferritin iron stores Á Metallomics Introduction How genetic variability affects metal accumulation has been studied in the agricultural context of plant bio-fortification to address nutritional deficiencies in humans (Palmer and Guerinot 2009; White and Broadley 2009). A major conclusion from these studies was that soil composition had a major influence on metal incorporation into plants. None- theless, genetic strains of plants with significant accumulations of one or more metals in different parts of the plant have been generated. On the other hand, and although a body of work has addressed the nutritional control of metal absorption and dietary aspects of animal metal homeostasis (Lonnerdal and M. Sadraie Á F. Missirlis (&) School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK e-mail: f.missirlis@qmul.ac.uk 123 Biometals (2011) 24:679–686 DOI 10.1007/s10534-011-9420-y