Convergent Molecular Evolution of Moth and Spider Silks

描述（由申请人提供）：适应的分子基础可能依赖于编码蛋白质的基因突变、基因表达方式的变化或两者的组合。评估适应的分子基础的一种方法是检查趋同进化案例背后的遗传结构，即远亲生物体中相似表型的独立进化。多个节肢动物谱系中蚕丝生产的独立进化为研究趋同分子进化提供了一个理想的模型系统。最初的重点是蜘蛛和蛾，数据库和分析方法开发这里将奠定基础，为未来的节肢动物丝生产的比较工作，通过实现以下目标。(1)通过从黑寡妇蜘蛛的多种组织类型中产生EST，将确定与蜘蛛丝生产特别相关的候选基因。一种新的统计方法将被应用于识别差异表达的基因，并将使用实验方法测试这些候选基因的丝腺特异性表达，大大提高了我们对蜘蛛丝生产的理解。(2)将比较家蚕和黑寡妇丝腺的表达模式，以确定基因表达的趋同是否可以部分解释丝生产的趋同进化。新的统计方法将被应用于评估表达模式的相似性，从不同的相关物种。这些发现将有助于理解趋同进化和适应的分子机制。(3)蜘蛛丝基因的推定调控区域将使用系统发育足迹法进行鉴定。将特异性靶向已知在蚕丝表达中重要的转录因子的结合基序。结合目标1和2，这些结果将提供对基因家族成员的组织特异性表达的进化的见解。 相关性：拟议的研究将拓宽目前对节肢动物基因表达的理解，节肢动物是一组众所周知的疾病载体，但也具有许多对人类有益的应用。此外，这项研究将通过鉴定伴侣蛋白和其他可能需要精确模仿天然蜘蛛丝的丝相关蛋白质，为人造丝的生产增加一个未探索的维度。这些人造丝可用于生物医学应用，如人造韧带或肌腱和令人难以置信的薄而坚固的缝合线。

DESCRIPTION (provided by applicant): The molecular basis for adaptations could rely on mutations in genes encoding proteins, changes in how genes are expressed, or a combination of both. One way to evaluate the molecular basis for adaptation is to examine the genetic architecture underlying cases of convergent evolution, the independent evolution of similar phenotypes in distantly related organisms. The independent evolution of silk production in multiple arthropod lineages provides an ideal model system to examine convergent molecular evolution. With an initial focus on spiders and moths, the databases and analytical methods developed here will lay the groundwork for future comparative work on arthropod silk production, through the achievement of the following goals. (1) Candidate genes specifically involved in spider silk production will be identified by generating ESTs from multiple tissue types of the black widow spider. A novel statistical method will be applied to identify differentially expressed genes and these candidate genes will be tested for silk gland specific expression using experimental methods, dramatically improving our understanding of spider silk production. (2) Expression patterns of the domesticated silkworm and black widow silk glands will be compared to determine if convergence in gene expression can, in part, explain convergent evolution of silk production. New statistical methods will be applied to evaluate the similarity of expression patterns from divergently related species. These findings will contribute to the understanding of the molecular mechanisms of convergent evolution and adaptation. (3) Putative regulatory regions of spider silk genes will be identified using phylogenetic footprinting. Binding motifs for transcription factors known to be important in silkworm silk expression will be specifically targeted. In combination with Goals 1 & 2, these results will provide insights into the evolution of tissue specific expression of gene family members. Relevance: The proposed research will broaden the current understanding of gene expression in arthropods, a group of animals that are well known for being disease vectors but also possess many beneficial applications for humans. Additionally, this research will add an unexplored dimension to the production of artificial silk by identifying chaperones and other silk-associated proteins that may be required for accurately mimicking native spider silk. These artificial silks can then be used in biomedical applications, such as artificial ligaments or tendons and incredibly thin but strong sutures.