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Open Access Highly Accessed Research article

Overlapping genes of Aedes aegypti: evolutionary implications from comparison with orthologs of Anopheles gambiae and other insects

Susanta K Behura and David W Severson*

Author Affiliations

Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA

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BMC Evolutionary Biology 2013, 13:124  doi:10.1186/1471-2148-13-124

Published: 18 June 2013

Abstract

Background

Although gene overlapping is a common feature of prokaryote and mitochondria genomes, such genes have also been identified in many eukaryotes. The overlapping genes in eukaryotes are extensively rearranged even between closely related species. In this study, we investigated retention and rearrangement of positionally overlapping genes between the mosquitoes Aedes aegypti (dengue virus vector) and Anopheles gambiae (malaria vector). The overlapping gene pairs of A. aegypti were further compared with orthologs of other selected insects to conduct several hypothesis driven investigations relating to the evolution and rearrangement of overlapping genes.

Results

The results show that as much as ~10% of the predicted genes of A. aegypti and A. gambiae are localized in positional overlapping manner. Furthermore, the study shows that differential abundance of introns and simple sequence repeats have significant association with positional rearrangement of overlapping genes between the two species. Gene expression analysis further suggests that antisense transcripts generated from the oppositely oriented overlapping genes are differentially regulated and may have important regulatory functions in these mosquitoes. Our data further shows that synonymous and non-synonymous mutations have differential but non-significant effect on overlapping localization of orthologous genes in other insect genomes.

Conclusion

Gene overlapping in insects may be a species-specific evolutionary process as evident from non-dependency of gene overlapping with species phylogeny. Based on the results, our study suggests that overlapping genes may have played an important role in genome evolution of insects.

Keywords:
Gene rearrangement; Culicidae; Genome evolution; Positionally overlapping genes; Negative selection