Crop-to-wild gene flow and spatial genetic structure in the closest wild relatives of the cultivated apple

Crop-to-wild gene flow have important evolutionary and ecological consequences and require careful consideration in conservation programs for wild genetic resources of potential use in breeding programs and in assessments of the risk of transgene escape into natural ecosystems. Using 26 microsatellites and a set of 1181 trees, we investigated the extent of introgression from the cultivated apple, Malus domestica, to its three closest wild relatives, M. sylvestris in Europe, M. orientalis in the Caucasus and M. sieversii in Central Asia. We found footprints of introgression from M. domestica to M. orientalis (3.2% of hybrids), M. sieversii (14.8%) and M. sylvestris (36.7%). Malus sieversii and M. orientalis presented weak but significant genetic structures across their geographic range. Malus orientalis displayed genetic differentiation with three differentiated populations in Turkey, Armenia and Russia. Malus sieversii consisted of a main population spread over Central Asia and a smalle...作物向野生近缘种的基因流（Crop-to-wild gene flow）具有重要的进化与生态学意义，在针对可用于育种项目的野生遗传资源的保护计划中，以及在评估转基因逃逸进入自然生态系统的风险时，均需予以审慎考量。本研究利用26个微卫星（microsatellites）标记与1181份树木样本，探究了栽培苹果（Malus domestica）向其3个近缘野生种的遗传渐渗程度：分别为分布于欧洲的林生苹果（Malus sylvestris）、高加索地区的东方苹果（Malus orientalis）以及中亚的塞威氏苹果（Malus sieversii）。研究发现，栽培苹果向东方苹果（杂交个体占比3.2%）、塞威氏苹果（14.8%）与林生苹果（36.7%）均存在渐渗痕迹。塞威氏苹果与东方苹果在其地理分布范围内呈现出微弱但显著的遗传结构。东方苹果在土耳其、亚美尼亚与俄罗斯境内分化为3个遗传分化显著的种群。塞威氏苹果由一个广泛分布于中亚的主体种群，以及一个小型……