Francisco Sara M, Robalo Joana I
MARE-Marine and Environmental Sciences Centre, ISPA-Instituto Universitário, Lisbon, Portugal.
PeerJ. 2020 May 1;8:e9098. doi: 10.7717/peerj.9098. eCollection 2020.
Extensive knowledge on the genetic characterization of marine organisms has been assembled, mainly concerning the spatial distribution and structuring of populations. Temporal monitoring assesses not only the stability in genetic composition but also its trajectory over time, providing critical information for the accurate forecast of changes in genetic diversity of marine populations, particularly important for both fisheries and endangered species management. We assessed fluctuations in genetic composition among different sampling periods in the western Portuguese shore in three fish species.
White seabream , sand smelt and shanny were chosen, because of their genetic patterns in distinct ecological environments, insight into historical and contemporary factors influencing population effective size ( ), and degree of commercial exploitation. Samples were obtained near Lisbon between 2003 and 2014 and screened for genetic variation with mitochondrial and nuclear markers. Analyses included genealogies, genetic diversities, temporal structures and contemporary .
For mtDNA no temporal structure was detected, while for nDNA significant differences were recorded between some sampling periods for the shanny and the sand smelt. Haplotype networks revealed deep genealogies, with various levels of diversification. The shanny revealed a smaller /generation when compared to the other species, which, in turn, revealed no evidence of genetic drift for most study periods. These results highlight the fact that temporal variations in genetic pool composition should be considered when evaluating the population structure of fish species with long distance dispersal, which are more vulnerable to recruitment fluctuations.
关于海洋生物遗传特征的广泛知识已经积累起来，主要涉及种群的空间分布和结构。时间监测不仅可以评估遗传组成的稳定性，还可以评估其随时间的变化轨迹，为准确预测海洋种群遗传多样性的变化提供关键信息，这对渔业和濒危物种管理都尤为重要。我们评估了葡萄牙西部海岸三种鱼类在不同采样时期的遗传组成波动情况。
选择了白鲷、沙鳗和锦鳚，原因在于它们在不同生态环境中的遗传模式、对影响种群有效大小（ ）的历史和当代因素的洞察以及商业开发程度。2003年至2014年期间在里斯本附近采集样本，并用线粒体和核标记筛选遗传变异。分析包括系谱、遗传多样性、时间结构和当代 。
对于线粒体DNA未检测到时间结构，而对于核DNA，锦鳚和沙鳗在一些采样时期之间记录到显著差异。单倍型网络显示出深度系谱，具有不同程度的分化。与其他物种相比，锦鳚的每代 较小，而其他物种在大多数研究时期没有遗传漂变的证据。这些结果突出了一个事实，即在评估具有远距离扩散能力、更容易受到补充波动影响的鱼类物种的种群结构时，应考虑基因库组成的时间变化。
