Comparative Genome Analysis of the Yellow Fever Mosquito Aedes aegypti with Drosophila melanogaster and the Malaria Vector Mosquito Anopheles gambiae

An in silico comparative genomics approach was used to identify putative orthologs to genetically mapped genes from the mosquito, Aedes aegypti, in the Drosophila melanogaster and Anopheles gambiae genome databases. Comparative chromosome positions of 73 D. melanogaster orthologs indicated significant deviations from a random distribution across each of the five A. aegypti chromosomal regions, suggesting that some ancestral chromosome elements have been conserved. However, the twogenomesalsoreflectextensivereshufflingwithinandbetweenchromosomalregions.Comparativechromosomepositions of A. gambiae orthologs indicate unequivocally that A. aegypti chromosome regions share extensive homology to the five A. gambiae chromosome arms. Whole-arm or near-whole-arm homology was contradicted with only two genes among the 75 A. aegypti genes for which orthologs to A. gambiae were identified. The two genomes contain large conserved chromosome segmentsthatgenerallycorrespondtobreak/fusionevents andareciprocaltranslocationwithextensiveparacentricinversions evidentwithin.Only very tightly linked genes arelikely toretain conserved linear orderswithin chromosome segments.TheD. melanogaster and A. gambiae genome databases therefore offer limited potential for comparative positional gene determinations among even closely related dipterans, indicating the necessity for additional genome sequencing projects with other dipteran species.