Duplication and divergence of opsins and chemoreceptors

基因复制事件与单个核苷酸替换一样常见。因此，同一物种的个体之间的基因数量有很大的差异。我的研究计划的目标是确定基因复制对分子和表型多样性的贡献。复制后的基因丢失模式可能对物种形成有重要的影响(Taylor等人，2001，Trends Genet，17：299)，然而，保留的重复是我目前研究的对象。我把重点放在感官受体上，因为这是分子和表型创新之间最明显的联系。项目一：我的实验室最近的研究表明，孔雀鱼比其他脊椎动物拥有更多对长波长敏感的视蛋白基因。我们将使用定量聚合酶链式反应、原位杂交以及与凯尔伯博士(隆德大学)合作的颜色辨别测试来检验这一假说：这些额外的视蛋白可以改善色觉。孔雀鱼是五颜六色的鱼，我们的实验将告诉我们它们是否也有特别好的色觉。项目2：我们是第一批在紫色海胆基因组中识别化学感觉基因的人之一(Burke等人，2006，devel Biol，300：434)。我们将进行一项基于聚合酶链式反应的调查，以确定化学感觉器官(海胆的鼻子)和原位杂交，以确定化学感觉细胞。通过在人胚胎肾细胞等细胞系中表达化学受体，我们还将通过测量cAMP、IP3或钙等次级信使水平的变化来研究不同化学受体对配体刺激的反应。项目3：我们将研究秀丽线虫化学感受器基因上游的重复非编码序列。化学感受器基因是该物种中最大的基因家族之一(约2000个基因)，但大多数在仅有的32个化学感觉神经元中的一个或多个中表达。由于许多基因在相同的神经元中表达，它们在调控基因表达的非编码DNA方面预计会有相似之处。我们将使用生物信息学、转基因蠕虫和荧光显微镜来表征化学受体基因调控模块。

Gene duplication events are as common as individual nucleotide substitutions. Consequently, gene number differs to a large extent among individuals of the same species. The goal of my research program is to characterize the contribution of gene duplication to molecular and phenotypic diversity. The pattern of gene loss after duplication might have important implications for speciation (Taylor et al., 2001, Trends Genet, 17:299), however, the duplicates that are retained are the subjects of my current research. I focus on sensory receptors because this is where the link between molecular and phenotypic innovation is most clear. Project 1: Recent research in my lab shows that guppies have more Long Wavelength Sensitive opsin genes than any other vertebrate. We will test the hypothesis these 'extra' opsins improve colour vision using qPCR, in situ hybridization and, in collaboration with Dr. Kelber (University of Lund), colour discrimination tests. Guppies are colourful fish and our experiments will tell us if they also have especially good colour vision. Project 2: We were among the first to identify chemosensory genes in the purple sea urchin genome (Burke et al., 2006, Devel Biol, 300:434). We will carry out a PCR-based survey of cDNA to identify chemosensory organs (the sea urchin "nose") and in-situ hybridization to identify chemosensory cells. By expressing chemoreceptors in a cell line such as human embryonic kidney cells we will also study the responses of different chemoreceeptors to ligand stimulation by measuring changes in the levels of secondary messengers such as cAMP, IP3, or calcium. Project 3: We will study duplicated non-coding sequences upstream of chemoreceptor genes in Caenorhabditis elegans. Chemoreceptor genes make up one of the largest gene families in this species (~2000 genes), yet most are expressed in one or more of only 32 chemosensory neurons. As many genes are expressed in the same neurons, they are expected to have similarities in the non-coding DNA that regulates gene expression. We will use bioinformatics, transgenic worms, and fluorescence microscopy to characterize chemoreceptor gene regulatory modules.