Estimating exotic gene flow into native pine stands: zygotic versus gametic components

Monitoring contemporary gene flow from widespread exotic plantations is becoming an important problem in forest conservation genetics. In plants, where both seed and pollen disperse, three components of exotic gene flow with potentially unequal consequences should be, but have not been, explicitly distinguished: zygotic, male gametic and female gametic. Building on a previous model for estimating contemporary rates of zygotic and male gametic gene flow among plant populations, we present here an approach that additionally estimates the third (female gametic) gene flow component, based on a combination of uni- and biparentally inherited markers. Using this method and a combined set of chloroplast and nuclear microsatellites, we estimate gene flow rates from exotic plantations into two Iberian relict stands of maritime pine (Pinus pinaster) and Scots pine (P. sylvestris). Results show neither zygotic nor female gametic gene flow but moderate (6–8%) male gametic introgression for both spec...

对广泛分布的外来人工林的当代基因流（gene flow）开展监测，已成为森林保护遗传学领域的重要研究方向。对于种子与花粉均可扩散的植物而言，外来基因流包含三个潜在影响不均等的组分，即合子型（zygotic）、雄配子型（male gametic）与雌配子型（female gametic）基因流，但此前尚未对其进行明确区分。本研究基于既往用于估算植物种群间合子型与雄配子型当代基因流频率的模型，提出了一种可额外估算第三种（雌配子型）基因流组分的新方法，该方法结合了单亲遗传与双亲遗传分子标记。本研究利用该方法并结合叶绿体微卫星与核微卫星组合标记，估算了外来人工林向伊比利亚半岛两处滨海松（Pinus pinaster）和欧洲赤松（P. sylvestris）孑遗林分的基因流频率。研究结果显示，两种松树均未出现合子型与雌配子型基因流，但均存在中等水平（6%~8%）的雄配子型基因渐渗。