DOES HABITAT AFFECT THE GENOMIC GC CONTENT? A LESSON FROM TELEOSTEAN FISH – A MINI REVIEW

The nature of the forces driving the genomic GC content of both prokaryotes and eukaryotes is matter of debate. Latest results favor selection as the main factor shaping base composition in bacteria. In vertebrates the subject is still under discussion. Focusing on teleostean fish, the mass specific routine metabolic rate temperature corrected using the Boltzmann's factor (MR) and base composition of genomes (GC%) were re-examined and related with their major habitats: polar, temperate, sub-tropical, tropical and deep-water. Fish of the polar habitat showed the highest MR. The MR of temperate fish was significantly higher than that of tropical one, which showed the lowest average value. Regarding GC%, polar and temperate fish both showed significantly higher values than both sub-tropical and tropical fish. Plotting MR and GC% a significant correlation was found between the two variables.