Rasmussen I R, Brødsgaard B
Institute of Plant Ecology, University of Copenhagen, Øster Farimagsgade 2D, DK-1353, Copenhagen K, Denmark.
Institute for Biological Chemistry B, University of Copenhagen, Sølvgade 83, DK-1307, Copenhagen K, Denmark.
Oecologia. 1992 Feb;89(2):277-283. doi: 10.1007/BF00317228.
Gene flow was investigated in a natural population of Lotus corniculatus L. (Fabaceae) using a combination of pollen and seed dispersal studies and a recombinant DNA technique. The population is spatially heterogeneous and grows with Empetrum nigrum. L. corniculatus is pollinated by the pollen-collecting bumblebee Bombus lapidarius L. Most pollinator flights occurred within patches, as bees usually visit nearest-neighbour plants, show no marked directionality, and forage mostly within patches. Gene flow by seeds is also limited, reinforcing the pattern of gene flow within patches. However, 2.6% of pollinator flights are between patches and considerable pollen carryover also occurs. Thus, gene flow between patches is potentially sufficient to retard or prevent genetic differentiation in spite of the patchy sub-structuring of the population. A sub-set of the population was analysed for restriction fragment length polymorphisms (RFLPs) to document the actual gene flow pattern of the population. The DNA analysis revealed significant levels of genetic differentiation between the patches. The level of gene flow that can be inferred from the distribution of genetic variation is surprisingly restricted, as compared to gene flow inferred from pollinator behaviour, and emphasizes that stochastic processes like genetic drift and founder effects may have a strong impact on the prevailing genetic structure.
利用花粉和种子传播研究以及重组DNA技术相结合的方法，对百脉根（豆科）的一个自然种群中的基因流动进行了研究。该种群在空间上是异质的，与黑果岩高兰伴生。百脉根由采集花粉的熊蜂拉氏熊蜂授粉。大多数传粉者飞行发生在斑块内，因为蜜蜂通常访问最近的邻居植物，没有明显的方向性，并且大多在斑块内觅食。种子的基因流动也受到限制，强化了斑块内的基因流动模式。然而，2.6%的传粉者飞行发生在斑块之间，并且也存在相当数量的花粉残留。因此，尽管种群存在斑块状的亚结构，但斑块间的基因流动可能足以延缓或阻止遗传分化。对该种群的一个子集进行了限制性片段长度多态性（RFLP）分析，以记录该种群的实际基因流动模式。DNA分析揭示了斑块之间存在显著水平的遗传分化。与从传粉者行为推断的基因流动相比，从遗传变异分布推断出的基因流动水平出人意料地受到限制，并强调遗传漂变和奠基者效应等随机过程可能对当前的遗传结构产生强烈影响。
