Rollins Lee A, Richardson Mark F, Shine Richard
Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University, Pigdons Road, Geelong, Vic., 3217, Australia.
Mol Ecol. 2015 May;24(9):2264-76. doi: 10.1111/mec.13184. Epub 2015 Apr 20.
The process of biological invasion exposes a species to novel pressures, in terms of both the environments it encounters and the evolutionary consequences of range expansion. Several invaders have been shown to exhibit rapid evolutionary changes in response to those pressures, thus providing robust opportunities to clarify the processes at work during rapid phenotypic transitions. The accelerating pace of invasion of cane toads (Rhinella marina) in tropical Australia during its 80-year history has been well characterized at the phenotypic level, including common-garden experiments that demonstrate heritability of several dispersal-relevant traits. Individuals from the invasion front (and their progeny) show distinctive changes in morphology, physiology and behaviour that, in combination, result in far more rapid dispersal than is true of conspecifics from long-colonized areas. The extensive body of work on cane toad ecology enables us to place into context studies of the genetic basis of these traits. Our analyses of differential gene expression from toads from both ends of this invasion-history transect reveal substantial upregulation of many genes, notably those involved in metabolism and cellular repair. Clearly, then, the dramatically rapid phenotypic evolution of cane toads in Australia has been accompanied by substantial shifts in gene expression, suggesting that this system is well suited to investigating the genetic underpinnings of invasiveness.
生物入侵过程使一个物种面临新的压力，这既体现在它所遇到的环境方面，也体现在其分布范围扩大所带来的进化后果上。已有研究表明，一些入侵物种会针对这些压力表现出快速的进化变化，从而为阐明快速表型转变过程中起作用的机制提供了有力契机。在热带澳大利亚，甘蔗蟾蜍（海蟾蜍，Rhinella marina）80年的入侵历史中，其入侵速度不断加快，这在表型层面已有充分描述，包括一些共同花园实验，这些实验证明了几种与扩散相关性状的遗传性。来自入侵前沿的个体（及其后代）在形态、生理和行为上表现出独特的变化，综合起来，其扩散速度比长期定居地区的同种个体要快得多。关于甘蔗蟾蜍生态学的大量研究工作使我们能够将这些性状的遗传基础研究置于相应背景中。我们对来自这一入侵历史断面两端蟾蜍的差异基因表达分析表明，许多基因显著上调，尤其是那些参与代谢和细胞修复的基因。显然，澳大利亚甘蔗蟾蜍显著快速的表型进化伴随着基因表达的大幅变化，这表明该系统非常适合用于研究入侵性的遗传基础。
