Correlated evolution is commonly observed when traits are functionally related. It is hypothesized that proteins involved in a pathway are likely to evolve in a correlated fashion, and coevolving gene families tend to undergo complementary gains and losses. Accordingly, gene copy numbers tend to show parallel changes during the evolution of coevolving gene families.

To test and verify this hypothesis, the research group headed by academician ZHANG Yaping from Kunming Institute of Zoology, Chinese Academy of Sciences observed correlated evolution by illustrating changes in the repertoire sizes of six gene families in 12 Drosophilagenomes: odorant-binding protein (OBP), odorant receptor (OR), gustatory receptor (GR), trypsin-like serine proteases (Tryp_SPc), cytochrome P450 (CYP450) and glutathione S-transferase (GST).

The observed correlations are indicative of parallel changes in the repertoire sizes of the six gene families that are due to similar demands for the quantity of these different genes in different lineages of Drosophila. Therefore, it is concluded that the correlated evolution among these six gene families in Drosophila is a signature of a parallel response to ecological adaptation. The main findings have been published in Genome Biology and Evolution.

The work has received grants from National Basic Research Program of China, National Natural Science Foundation of China and Bureau of Science and Technology of Yunnan Province.