Tagg N, Innes D J, Doncaster C P
School of Biological Sciences, University of Southampton, Southampton, SO16 7PX, UK.
Oecologia. 2005 May;143(4):527-36. doi: 10.1007/s00442-005-0016-5. Epub 2005 Mar 24.
Ecological theory predicts that genetic variation produced by sexual reproduction results in niche diversification and provides a competitive advantage both to facilitate invasion into genetically uniform asexual populations and to withstand invasion by asexual competitors. We tested the hypothesis that a large group of diverse clones of Daphnia obtusa has greater competitive advantage when invading into genetically uniform populations of this species than a smaller group with inherently less genetic diversity. We compared competitive outcomes to those of genetically uniform groups of small and large size invading into genetically diverse populations. Genetically diverse invaders of initially large group size increased their representation by more than those of initially small size; in contrast, genetically uniform invaders of initially large group size diminished on average by more than those of initially small size. These results demonstrate an advantage to the genetic variation produced by sexual reproduction, both in invasion and resisting invasion, which we attribute to competitive release experienced by individuals in genetically diverse populations.
生态理论预测，有性生殖产生的遗传变异会导致生态位多样化，并提供竞争优势，既有利于入侵基因一致的无性种群，也能抵御无性竞争者的入侵。我们检验了这样一个假设：一大组不同的钝额溞克隆体在入侵该物种基因一致的种群时，比一小组遗传多样性固有较低的克隆体具有更大的竞争优势。我们将竞争结果与大小不同的基因一致的群体入侵基因多样的种群时的结果进行了比较。最初群体规模大的基因多样的入侵者比最初群体规模小的入侵者增加了更多的占比；相反，最初群体规模大的基因一致的入侵者平均减少的幅度比最初群体规模小的入侵者更大。这些结果表明，有性生殖产生的遗传变异在入侵和抵御入侵方面都具有优势，我们将其归因于基因多样的种群中个体所经历的竞争释放。
