The olfactory gene repertoire in salmonids

长期以来，生物学家和公众一直着迷于鲑鱼进行长途海洋旅行并导航返回其出生溪流的能力。鲑鱼利用嗅觉线索在淡水中迁徙回产卵地。这种忠实的回归建立了鲑鱼的种群结构，使它们能够适应当地的条件。我的研究项目的潜在目标是了解嗅觉在决定鲑鱼如何返回出生地的过程中所起的作用。拟议的研究利用了基因组资源，这些资源是我在之前的大型鲑鱼基因组项目中帮助开发的，最终在大西洋鲑鱼基因组测序国际合作中达到顶峰。此外，它将建立在我实验室最近对大西洋鲑鱼嗅觉受体基因特征的研究基础上。嗅觉受体分为四类：V1Rs （oras）、V2Rs （OlfCs）、MORs和TAARs。我小组的一名实习生K. Johnstone（2012年博士学位）在大西洋鲑鱼和许多MORs中发现了所有的ora和OlfC基因。拟议研究的第一个目标是完成大西洋鲑鱼嗅觉受体基因的清单。这将为开展嗅觉受体功能及其基因调控的研究提供必要的基础信息。如果嗅觉感受器对鲑鱼洄游到不同的河流系统起作用，那么不同的鲑鱼种群，特别是那些具有不同生活史策略的鲑鱼种群，应该有不同的嗅觉感受器补体。根据这一假设，研究计划的第二个目标是检查纽芬兰两个大西洋鲑鱼种群的幼鱼、幼鱼和归来的成年鲑鱼中所有类别的嗅觉受体的表达模式，并寻找这些种群之间的等位基因变异。第三个目标是将研究范围扩大到红鲑鱼和非洄游鲑鱼，这两种鲑鱼在不同的生态位中都有明确的种群。这一研究项目将有助于更好地了解鲑鱼的迁徙和当地适应性，这将对野生鲑鱼的保护具有实际意义。

The ability of salmon to undertake long marine journeys and to navigate their way back to their natal streams has long fascinated biologists and the public alike. Salmon use olfactory cues in their freshwater migration back to the spawning grounds. This faithful return establishes the population structure of salmon, and enables them to adapt to local conditions. The underlying objective of my research program is to understand the role of olfaction in determining how salmon return to their birthplace. The proposed research takes advantage of the genomic resources that I helped develop through previous large scale salmon genomics projects culminating in the International Cooperation to Sequence the Atlantic Salmon Genome. In addition, it will build on recent work in my laboratory on the characterization of olfactory receptor genes in Atlantic salmon. There are four classes of olfactory receptors: V1Rs (oras), V2Rs (OlfCs), MORs and TAARs. A trainee in my group, K. Johnstone (PhD 2012), identified all of the ora and OlfC genes in Atlantic salmon and many of the MORs. The first goal of the proposed research is to complete the inventory of the olfactory receptor genes in Atlantic salmon. This will provide the basic information necessary to carry out research into the function of olfactory receptors and how their genes are regulated. If olfactory receptors contribute to the homing of salmon to different river systems, then different salmon populations, especially those with different life history strategies, should have different complements of olfactory receptors. In keeping with this hypothesis, the second goal of the research program is to examine the expression patterns of all classes of olfactory receptors in juveniles, smolts and returning adults from two anadromous and one resident population of Atlantic salmon in Newfoundland, and to search for allelic variation between these populations. The third goal is to expand the studies to sockeye salmon and kokanee, the non-migratory form, both of which have well-defined populations in different ecological niches. This program of research will lead to a better understanding of salmon migration and local adaptation, which will have practical implications for the conservation of wild salmon.