The assessment of population structure and genetic diversity is crucial for the management and conservation of threatened species. Natural and artificial barriers to dispersal (i.e., gene flow) increase populations’ differentiation and isolation by reducing genetic exchange and diversity. Freshwater ecosystems are highly fragmented because of human activities. Threatened species with small population sizes are more sensitive to habitat fragmentation effects. Here, we investigate the genetic population structure and gene flow among seven populations of Aphanius sophiae in the Kor Basin by using sequences of the complete Cyt b gene and otolith morphometry. The Cyt b gene showed low level of genetic variation, only 4.12% of the identified sites were variable, and 2.42% were parsimony informative. Overall, haplotype diversity was low to moderate and nucleotide diversity was low to extremely low. Fish populations exhibited high levels of genetic differentiation, suggesting limited gene flow among them. These differences were obtained not only among geographically distant populations, but also among neighboring localities. Genetic population structure was supported by the AMOVA analysis and by the haplotype network (only one of 21 haplotypes were shared by two localities). Otolith morphometric analysis was in agreement with genetic results, the two most distant and isolated populations were clearly separated, and genetically close populations showed less differences in morphometry. A significant pattern of isolation by distance was also detected among A. sophiae populations, with genetic distance more correlated with hydrological distance than with geographic distance. Results suggested that limited gene flow due to habitat fragmentation is an important factor contributing to genetic structuring and to the loss of genetic variation of A. sophiae populations. Aphanius sophiae population structure seems to be the result of habitat fragmentation and water pollution, but other factors such as introduced species should be considered. Given the high degree of genetic structuring, the definition of conservation groups is of particular importance for A. sophiae, which should be considered endangered according to the IUCN criteria. Conservation plans must recognize the genetic independence of populations and manage separately preventing the loss of locally adapted genotypes.

中文翻译：

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从遗传学和耳石形态学推断受威胁的地方性犬齿蛇（Aphanius sophiae）的零散种群的多样性和结构：对保护和管理的意义

种群结构和遗传多样性的评估对于受威胁物种的管理和保护至关重要。传播的自然和人为障碍（即基因流）通过减少遗传交换和多样性来增加人群的分化和隔离。由于人类活动，淡水生态系统高度分散。种群数量较小的受威胁物种对生境破碎化影响更为敏感。在这里，我们使用完整的Cyt b基因序列和耳石形态学研究了Kor盆地七个Aphanius sophiae种群的遗传种群结构和基因流。Cyt b该基因显示出低水平的遗传变异，只有4.12％的已鉴定位点是可变的，而2.42％具有简约信息。总体而言，单倍型多样性低至中等，核苷酸多样性低至极低。鱼类种群显示出高水平的遗传分化，表明其中的基因流动有限。这些差异不仅在地理上遥远的人群之间，而且在邻近地区之间也存在。遗传种群结构得到AMOVA分析和单倍型网络的支持（两个地区仅共享21个单倍型之一）。耳石形态分析与遗传结果一致，两个最远和最孤立的种群被清楚地分开，并且遗传上接近的种群在形态上的差异较小。phi桐种群的遗传距离与水文距离的相关性远大于地理距离。结果表明，由于生境破碎而导致的有限基因流是导致遗传结构和造成A. sophiae种群遗传变异丧失的重要因素。楠楠种群结构似乎是生境破碎化和水污染的结果，但应考虑其他因素，例如引进物种。鉴于高度的遗传结构，保护基团的定义对于A. sophiae尤为重要，根据IUCN标准应视为濒临灭绝。保护计划必须认识到种群的遗传独立性，并分别进行管理，以防止失去适应当地的基因型。