, 2012) and membrane spanning proteins only (Patel et al., 2010) have consistently identified that microbial function is more strongly correlated to ‘environmental’ distance (as defined by variability in available metadata such as temperature, nutrients, sunlight, etc) than either geographic distance or taxonomic distance. Microbial functional components that vary in relation to environmental parameters in these cases

selleckchem have included strategies of energy conversion (Gianoulis et al., 2009 and Jiang et al., 2012), cofactor synthesis (Gianoulis et al., 2009), phosphate and iron acquisition (Patel et al., 2010), cell signaling and phage associated activity (Jiang et al., 2012). Thus distinct ocean environments maintain a metabolic footprint that is imprinted on the genomic content of its microbial inhabitants (Gianoulis et al., 2009). Longhurst’s provinces provided an important meeting point for biologists and oceanographers PD0325901 clinical trial to organize their observations onto a common geographical framework. Ongoing work defining the functional or metabolic biogeography of the oceans in terms of genomics promises to provide new meeting points for microbial ecologists, oceanographers, biogeochemists and molecular biologists. Environmental selection on genomic traits rather than taxa is not limited to gene content but extends to specific resource usage, which differs in different provinces of the marine

environment. There are at least two examples where genome architecture has been shown to be an important adaptation. One is cost minimization to keep protein mass as small as possible without

sacrificing function and the other is cost minimization to minimize requirements for potentially limiting nutrients such as C, N, S, P or Fe. When an amino acid substitution does not alter the fitness of a specific protein, evolution favors using a smaller amino acid. Indeed, in general across life, basic thermodynamics or cost minimization means smaller amino acids are found in higher frequencies than larger ones (Seligman, 2003). Further, analysis of C, N and S assimilatory proteins indicates that evolution favors reducing the frequencies of the atom in a specific assimilatory pathway (Baudouin-Cornu et al., 2001). Thus, in comparison to the rest of the genome, the sulfur assimilatory pathway Methane monooxygenase proteins have fewer cysteine and methionine amino acids than other proteins. Not surprisingly, it is poor economics to have to make sulfur rich proteins if you need to acquire and assimilate more sulfur. Grzymski and Dussaq (2012) extended these concepts further and hypothesized that in oligotrophic oceans organisms are under constant pressure to increase N and Fe use efficiency and should have highly cost minimized genomes. The authors highlighted two important trends in successful oligotrophic organisms — they tend to be AT rich and this skews their amino acid usage to those with fewer N atoms in side chains.