Duda T F, Remigio E A
Department of Ecology and Evolutionary Biology & Museum of Zoology, University of Michigan, 1109 Geddes Avenue, Ann Arbor, MI 48109, USA.
Mol Ecol. 2008 Jun;17(12):3018-32. doi: 10.1111/j.1365-294X.2008.03804.x. Epub 2008 May 16.
Venoms of predatory marine gastropods of the genus Conus show amazing levels of interspecific diversity and are comprised of a cocktail of peptide neurotoxins, termed conotoxins, that are encoded by large gene families. Conotoxin gene family evolution is characterized by gene duplications and high rates of nonsynonymous substitution among paralogues; yet, what controls the differentiation of venoms among species is not clear. We compared four-loop conotoxin transcripts of six closely related Conus species to examine conotoxin expression patterns among species. The species examined appear to express different numbers of four-loop conotoxin loci and similarity in expression patterns does not seem to correspond with phylogenetic affinity. Moreover, several loci appear to have been independently silenced while others appear to have been revived from previously silenced states. Some loci also appear to exhibit coordinated expression patterns. These results suggest that the evolution of conotoxin expression patterns is incredibly dynamic and the differentiation of venoms of Conus is controlled in part by the evolution of unique conotoxin expression patterns.
芋螺属掠食性海洋腹足纲动物的毒液呈现出惊人的种间多样性水平，由多种肽类神经毒素混合而成，这些毒素被称为芋螺毒素，由庞大的基因家族编码。芋螺毒素基因家族的进化特征是基因重复以及旁系同源物之间非同义替换率较高；然而，物种间毒液分化的控制因素尚不清楚。我们比较了六种近缘芋螺物种的四环芋螺毒素转录本，以研究物种间芋螺毒素的表达模式。所研究的物种似乎表达不同数量的四环芋螺毒素基因座，并且表达模式的相似性似乎与系统发育亲缘关系不对应。此外，一些基因座似乎已独立沉默，而其他基因座似乎已从先前的沉默状态中恢复。一些基因座似乎也表现出协调的表达模式。这些结果表明，芋螺毒素表达模式的进化极其动态，芋螺毒液的分化部分受独特芋螺毒素表达模式进化的控制。
