Evo-devo: Doing the time warp
| Autor: | Louisa, Flintoft |
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| Rok vydání: | 2011 |
| Předmět: | |
| Zdroj: | PLoS Biology |
| ISSN: | 1471-0064 |
| Popis: | Evolving organs are seen as clusters of discordant genes on the heatmaps representing cross-species comparisons of developmental gene expression data. Evolutionary innovations can be driven by spatial and temporal changes in gene expression. Several such differences have been documented in the embryos of lower and higher Diptera. One example is the reduction of the ancient extraembryonic envelope composed of amnion and serosa as seen in mosquitoes to the single amnioserosa of fruit flies. We used transcriptional datasets collected during the embryonic development of the fruit fly, Drosophila melanogaster, and the malaria mosquito, Anopheles gambiae, to search for whole-genome changes in gene expression underlying differences in their respective embryonic morphologies. We found that many orthologous gene pairs could be clustered based on the presence of coincident discordances in their temporal expression profiles. One such cluster contained genes expressed specifically in the mosquito serosa. As shown previously, this cluster is redeployed later in development at the time of cuticle synthesis. In addition, there is a striking difference in the temporal expression of a subset of maternal genes. Specifically, maternal transcripts that exhibit a sharp reduction at the time of the maternal-zygotic transition in Drosophila display sustained expression in the Anopheles embryo. We propose that gene clustering by local temporal discordance can be used for the de novo identification of the gene batteries underlying morphological diversity. Author Summary Linking genotype to phenotype is a major undertaking in modern biological research. A variety of strategies are used but have generally failed to explain the maintenance and acquisition of new phenotypic traits in changing populations. We propose that whole-genome cross-species comparisons can be used to identify gene clusters underlying phenotypic variation. In the present study we used gene expression datasets collected during fruit fly and mosquito embryogenesis to identify temporal changes in gene expression. We found that differentially represented tissue types (such as extraembryonic serosa) were clearly manifested by clusters of local discordances in gene expression. Discordances were also observed for a suite of maternally expressed genes, consistent with the notion that the abrupt maternal-zygotic transition seen in Drosophila is an evolutionary innovation of higher Diptera. We propose that gene clustering by expression discordance can be used to determine the genetic basis of phenotypic variation. |
| Databáze: | OpenAIRE |
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