PDF(Pubmed)
Abstract：
Genetic diversity can modulate a population\'s response to a changing environment and plays a critical role in its ecological function. While multiple processes act to maintain genetic diversity, sexual reproduction remains the primary driving force. Eelgrass (Zostera marina) is an important habitat-forming species found in temperate coastal ecosystems across the globe. Recent increases in sea surface temperatures have resulted in shifts to a mixed-annual life-history strategy (i.e., displaying characteristics of both annual and perennial meadows) at its southern edge-of-range. Given that mating systems are intimately linked to standing levels of genetic variation, understanding the scope of sexual reproduction can illuminate the processes that shape genetic diversity. To characterize edge-of-range eelgrass mating systems, developing seeds on flowering Z. marina shoots were genotyped from three meadows in Topsail, North Carolina. In all meadows, levels of multiple mating were high, with shoots pollinated by an average of eight sires (range: 3-16). The number of fertilized seeds (i.e., reproductive success) varied significantly across sires (range: 1-25) and was positively correlated with both individual heterozygosity and self-fertilization. Outcrossing rates were high (approx. 70%) and varied across spathes. No clones were detected, and kinship among sampled flowering shoots was low, supporting observed patterns of reproductive output. Given the role that genetic diversity plays in enhancing resistance to and resilience from ecological disturbance, disentangling the links between life history, sexual reproduction, and genetic variation will aid in informing the management and conservation of this key foundation species.
摘要：
遗传多样性可以调节种群对环境变化的反应，并在其生态功能中起着至关重要的作用。虽然多个过程可以维持遗传多样性，有性生殖仍然是主要的驱动力。Eelgrass（Zosteramarina）是在全球温带沿海生态系统中发现的重要栖息地形成物种。最近海面温度的升高导致转向混合年度生活史策略(即，在其南部边缘显示一年生和多年生草甸的特征）。鉴于交配系统与遗传变异的站立水平密切相关，了解有性生殖的范围可以阐明塑造遗传多样性的过程。为了表征边缘鳗草交配系统，在开花的Z.滨海芽上发育的种子从Topsail的三个草地上进行了基因分型，北卡罗来纳州。在所有的草地上，多次交配的水平很高，平均由八个父亲授粉的枝条（范围：3-16）。受精种子的数量(即，生殖成功）在父系之间差异显着（范围：1-25），并且与个体杂合性和自我受精呈正相关。杂交率高（约。70％），并且在不同的情况下变化。没有检测到克隆,采样的开花芽之间的亲缘关系很低，支持观察到的生殖输出模式。鉴于遗传多样性在增强对生态干扰的抵抗力和抵御能力方面的作用，解开生活史之间的联系，有性生殖,遗传变异将有助于为这一关键基础物种的管理和保护提供信息。
