Department of Molecular and Cell Biology, Division of Genetics Genomics and Development, Center for Integrative Genomics, University of California, Berkeley, California, United States of America.
PLoS Biol. 2011 Jan 25;9(1):e1000584. doi: 10.1371/journal.pbio.1000584.
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 re-deployed 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.
进化创新可以由基因表达的时空变化所驱动。在较低和较高的双翅目昆虫的胚胎中已经记录了几种这样的差异。一个例子是，像在蚊子中看到的由羊膜和浆膜组成的古老的胚胎外膜减少到果蝇的单一羊膜浆膜。我们使用在果蝇发育过程中收集的转录数据集，黑腹果蝇，和疟蚊，冈比亚按蚊，寻找导致它们各自胚胎形态差异的全基因组基因表达变化。我们发现，许多直系基因对可以根据其时间表达谱中的一致不和谐来聚类。这样的一个聚类包含在蚊子浆膜中特异性表达的基因。如前所述，该聚类在以后的发育过程中，在角质层合成时重新部署。此外，一组母体基因的时空表达存在显著差异。具体来说，在果蝇的母体-合子过渡时表现出急剧减少的母体转录本在冈比亚按蚊胚胎中持续表达。我们提出，通过局部时间不和谐进行基因聚类可以用于从头鉴定形态多样性的基因电池。
