Laboratorio de Genética para la Conservación, Centro de Investigaciones Biológicas del Noroeste, La Paz, Baja California Sur, México.
Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Departamento de Plancton y Ecología Marina, La Paz, Baja California Sur, México.
PLoS One. 2018 Mar 26;13(3):e0194646. doi: 10.1371/journal.pone.0194646. eCollection 2018.
Determining the relative influence of biotic and abiotic factors on genetic connectivity among populations remains a major challenge in evolutionary biology and in the management and conservation of species. North Pacific hake (Merluccius productus) inhabits upwelling regions in the California Current ecosystem from the Gulf of California to the Gulf of Alaska. In this study, we examined mitochondrial DNA (mtDNA) and microsatellite variation to estimate levels of genetic differentiation of M. productus in relation to the role of oceanographic features as potential barriers to gene flow. Samples were obtained from nine sites spanning a large part of the geographic range of the species, from Puget Sound, Washington to Costa Rica. The microsatellite results revealed three genetically discrete populations: one spanning the eastern Pacific coast, and two apparently resident populations circumscribed to the Puget Sound and the northern Gulf of California (FST = 0.032, p = 0.036). Cytochrome b sequence data indicated that isolation between the Puget Sound and northern Gulf of California populations from the coastal Pacific were recent phenomena (18.5 kyr for Puget Sound and 40 kyr for the northern Gulf of California). Oceanographic data obtained from the Gulf of California support the hypothesis that permanent fronts within the region, and strong gradients at the entrance to the Gulf of California act as barriers to gene flow. A seascape genetics approach found significant genetic-environment associations, where the daytime sea surface temperature and chlorophyll concentrations were the best predictive variables for the observed genetic differentiation. Considering the potential causes of genetic isolation among the three populations, e.g. spawning areas in different latitudes associated with upwelling processes, oceanographic barriers, asymmetric migration and specialized diet, oceanographic barriers appear to be a likely mechanism restricting gene flow.
确定生物和非生物因素对种群间遗传连通性的相对影响仍然是进化生物学以及物种管理和保护的主要挑战。北太平洋无须鳕（Merluccius productus）栖息在加利福尼亚洋流生态系统的上升流区域，从加利福尼亚湾延伸到阿拉斯加湾。在这项研究中，我们研究了线粒体 DNA（mtDNA）和微卫星变异，以评估与海洋特征作为潜在基因流动障碍的作用相关的 M. productus 遗传分化水平。样本取自跨越物种地理范围大部分地区的九个地点，从华盛顿州的普吉特湾到哥斯达黎加。微卫星结果显示出三个遗传上不同的种群：一个种群横跨东太平洋海岸，另外两个种群显然局限于普吉特湾和北加利福尼亚湾（FST = 0.032，p = 0.036）。细胞色素 b 序列数据表明，普吉特湾和北加利福尼亚湾种群与太平洋沿海地区之间的隔离是最近发生的现象（普吉特湾为 18.5 千年前，北加利福尼亚湾为 40 千年前）。从加利福尼亚湾获得的海洋学数据支持这样的假设，即该地区内的永久性锋面和加利福尼亚湾入口处的强梯度是基因流动的障碍。景观遗传学方法发现了显著的遗传-环境关联，其中白天的海面温度和叶绿素浓度是预测观察到的遗传分化的最佳变量。考虑到三个种群之间遗传隔离的潜在原因，例如与上升流过程相关的不同纬度的产卵区、海洋学障碍、不对称迁移和专门的饮食，海洋学障碍似乎是限制基因流动的一种可能机制。
