Researchers at the Kunming Institute of Zoology (KIZ)of Chinese Academy of Sciences (CAS) found that the energy demand of animals influences the selection pressure on their mitochondrial-encoded proteins.

Mitochondria are regarded as the power plant of cells, which play critical roles not only in energy metabolism, but also in thermo-regulation. However, the relative importance of the two roles is still rarely considered.

Here the team headed by CAS member ZHANG Yaping of KIZ conducted a comparative genomic analysis of 401 teleost complete mitochondrial genomes in Genbankof US National Institute of Health to evaluate the roles of energetic functional constraints on teleost mitochondrial-encoded protein evolution.

They found that mitochondrial protein-coding genes of migratory fishes have significantly smaller Ka/Ks than non-migratory fishes. The same dataset showed that the genes of fishes living in cold climates have significantly smaller Ka/Ks than tropical fishes. In contrast, these trends were not observed for two nuclear genes that are not involved in energy metabolism.

The researchers concluded that the differences in selection patterns between mitochondrial and nuclear genes suggest the functional constraints acting on mitochondria, due to energy metabolism and/or thermo-regulation, influence the evolution of mitochondrial-encoded proteins in teleosts.

Their findings has been published in Molecular Biology and Evolution(http://mbe.oxfordjournals.org/content/early/2010/10/05/molbev.msq256.abstract).