Comparison of the oxidative phosphorylation (OXPHOS) nuclear genes in the genomes of Drosophila melanogaster, Drosophila pseudoobscura and Anopheles gambiae.
BACKGROUND
In eukaryotic cells, oxidative phosphorylation (OXPHOS) uses the products of both nuclear and mitochondrial genes to generate cellular ATP. Interspecies comparative analysis of these genes, which appear to be under strong functional constraints, may shed light on the evolutionary mechanisms that act on a set of genes correlated by function and subcellular localization of their products.


RESULTS
We have identified and annotated the Drosophila melanogaster, D. pseudoobscura and Anopheles gambiae orthologs of 78 nuclear genes encoding mitochondrial proteins involved in oxidative phosphorylation by a comparative analysis of their genomic sequences and organization. We have also identified 47 genes in these three dipteran species each of which shares significant sequence homology with one of the above-mentioned OXPHOS orthologs, and which are likely to have originated by duplication during evolution. Gene structure and intron length are essentially conserved in the three species, although gain or loss of introns is common in A. gambiae. In most tissues of D. melanogaster and A. gambiae the expression level of the duplicate gene is much lower than that of the original gene, and in D. melanogaster at least, its expression is almost always strongly testis-biased, in contrast to the soma-biased expression of the parent gene.


CONCLUSIONS
Quickly achieving an expression pattern different from the parent genes may be required for new OXPHOS gene duplicates to be maintained in the genome. This may be a general evolutionary mechanism for originating phenotypic changes that could lead to species differentiation.
Tripoli
Gaetano
G
University of Bari, DAPEG Section of Genetics, via Amendola 165/A, 70126 Bari, Italy. g.tripoli@biologia.uniba.it
D'Elia
Domenica
D
Barsanti
Paolo
P
Caggese
Corrado
C
D000818:Animals; D000852:Anopheles / Q000235:genetics*; D002467:Cell Nucleus / Q000235:genetics; D002874:Chromosome Mapping; D003062:Codon; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics; D004331:Drosophila melanogaster / Q000235:genetics*; D020440:Gene Duplication; D015870:Gene Expression; D017344:Genes, Insect; D049750:Genome, Insect; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D007438:Introns; D024101:Mitochondrial Proteins / Q000235:genetics* / Q000378:metabolism; D010085:Oxidative Phosphorylation; D017386:Sequence Homology, Amino Acid; D026801:Synteny
D003062:Codon; D029721:Drosophila Proteins; D019476:Insect Proteins; D024101:Mitochondrial Proteins