太平洋牡蛎Crassostreagigas,亚洲沿海特有的,在过去的一个世纪里一直在全球转移,导致自我维持的引入群体(归化)。世界许多地方的牡蛎水产养殖业依靠市售种子(孵化场养殖)或归化/野生牡蛎进入农场(归化养殖)。因此,了解种群和农场类型之间的遗传变异非常重要。这里,我们对来自法国的归化/野生种群进行基因分型,Japan,中国,最广泛的是沿海不列颠哥伦比亚省,加拿大。我们还对整个北半球的养殖种群进行了基因型分析,以与归化种群进行比较。总的来说,使用双消化RAD测序在182个归化,112孵化场养殖,和72只归化养殖牡蛎(n=366)。与以前的研究一致,在温哥华岛周围观察到非常低的遗传分化(平均FST=0.0019),而在日本-加拿大-法国历史易位谱系中的国家之间的分化较低(法国-加拿大FST=0.0024;日本-加拿大FST=0.0060)。中国人口差异更大(中日FST=0.0241)。孵化繁殖的种群具有较高的个体间亲密关系,表明家庭结构。在农场没有发现种群内近亲繁殖,但一个农场种群的核苷酸多样性和多态性率较低。将牡蛎从大自然转移到农场并没有导致强大的代内选择。在不列颠哥伦比亚省的几个孵化场种群中发现了相当频繁的私人等位基因,暗示非本地起源。选择测试确定的异常位点与与驯化相关的选择性差异一致,在某些情况下,在多个农场中一致识别。最突出的异常候选是参与钙信号传导和钙调蛋白活性的附近基因。孵化场养殖牡蛎潜在渗入的含义取决于归化种群是否被视为当地适应的资源或被引入的资源,入侵物种。鉴于BC行业的价值和行业面临的挑战(例如,气候变化,作物损失,生物应激源),这仍然是一个重要的问题。
Pacific oyster Crassostrea gigas, endemic to coastal Asia, has been translocated globally throughout the past century, resulting in self-sustaining introduced populations (naturalized). Oyster aquaculture industries in many parts of the world depend on commercially available seed (
hatchery-farmed) or naturalized/wild oysters to move onto a farm (naturalized-farmed). It is therefore important to understand genetic variation among populations and farm types. Here, we genotype naturalized/wild populations from France, Japan,
China, and most extensively in coastal British Columbia, Canada. We also genotype cultured populations from throughout the Northern Hemisphere to compare with naturalized populations. In total, 16,942 markers were identified using double-digest RAD-sequencing in 182 naturalized, 112 hatchery-farmed, and 72 naturalized-farmed oysters (n = 366). Consistent with previous studies, very low genetic differentiation was observed around Vancouver Island (mean F ST = 0.0019) and low differentiation between countries in the Japan-Canada-France historical translocation lineage (France-Canada F ST = 0.0024; Japan-Canada F ST = 0.0060). Chinese populations were more differentiated (
China-Japan F ST = 0.0241).
Hatchery-propagated populations had higher interindividual relatedness suggesting family structure. Within-population inbreeding was not detected on farms, but nucleotide diversity and polymorphism rate were lower in one farm population. Moving oysters from nature onto farms did not result in strong within-generation selection. Private alleles at substantial frequency were identified in several
hatchery populations grown in BC, suggesting nonlocal origins. Tests of selection identified outlier loci consistent with selective differences associated with domestication, in some cases consistently identified in multiple farms. Top outlier candidates were nearby genes involved in calcium signaling and calmodulin activity. Implications of potential introgression from hatchery-farmed oysters depend on whether naturalized populations are valued as a locally adapted resource or as an introduced, invasive species. Given the value of the industry in BC and the challenges the industry faces (e.g., climate change, crop losses, biotic stressors), this remains an important question.