Abstract
Phylogenetic analysis of heme peroxidases (HPXs) of Culicidae and other insects revealed six highly conserved ancient HPX lineages, each of which originated by gene duplication prior to the most recent common ancestor (MRCA) of Hemimetabola and Holmetabola. In addition, culicid HPX7 and HPX12 arose by gene duplication after the MRCA of Culicidae and Drosophilidae, while HPX2 orthologs were not found in any other order analyzed except Diptera. Within Diptera, HPX2, HPX7, and HPX12 were relatively poorly conserved at the amino acid level in comparison to the six ancient lineages. The genome of Anopheles gambiae included genes ecoding five proteins (HPX10, HPX11, HPX13, HXP14, and HPX15) without ortholgs in other genomes analyzed. Overall, gene expression patterns did not seem to reflect phylogenetic relationships, but genes that evolved rapidly at the amino acid sequence level tended to have divergent expression patterns as well. The uniquely high level of duplication of HPXs in A. gambiae may have played a role in coevolution with malaria parasites.
