Energetics and population genetics at the root of eukaryotic cellular and genomic complexity

In PNAS, Lynch and Marinov provide detailed estimates of the energy cost associated with the addition of new coding or noncoding sequences to prokaryotic and eukaryotic genomes (1). The amount of ATP that is expended at each step of information transfer is derived from the known biochemistry of these processes and an extensive collection of data on gene expression, as well as nucleic acid and protein decay for diverse organisms. The energy cost is then transformed into fitness cost via a simple, intuitive notion that fitness cost is proportional to the fraction of the total energy expenditure of a cell that is attributable to the maintenance of a given sequence.