Whittle C-A, Johnston M O
Department of Zoology, University of British Columbia, Vancouver, Canada.
J Exp Bot. 2006;57(9):1847-55. doi: 10.1093/jxb/erj155. Epub 2006 May 10.
Currently, the types of factors that impact the mutation rate is a controversial issue. The marked attention towards identifying the factors that impact the genomic mutation rate is justified because mutations are the source of genetic variation underlying evolution and because many mutations have deleterious effects and can cause diseases. Although data showing correlations between germ cell division number and mutation rates (from epidemiological studies and molecular evolutionary rate analyses) have suggested that most mutations in animals are replication errors, this notion is highly debated and inconsistencies in the correlations suggest that other, replication-independent factors, could play an important role. Likely candidates include environmental parameters and cell age, but these issues have proved to be difficult to study using animals and in vitro systems, and consequently, very few or no data currently exist. The specific features of plants that make them powerful model systems for revealing the influence of the environment (natural environmental factors) and cell age on the spontaneous genomic mutation rate are discussed here. Overall, the evidence suggests that plants could be key biological systems for advancing our knowledge about how and why heritable mutations arise.
目前，影响突变率的因素类型是一个有争议的问题。对识别影响基因组突变率的因素给予高度关注是合理的，因为突变是进化背后遗传变异的来源，而且许多突变具有有害影响并可导致疾病。尽管显示生殖细胞分裂次数与突变率之间相关性的数据（来自流行病学研究和分子进化速率分析）表明动物中的大多数突变是复制错误，但这一观点存在激烈争论，相关性中的不一致表明其他与复制无关的因素可能起重要作用。可能的候选因素包括环境参数和细胞年龄，但事实证明，使用动物和体外系统研究这些问题很困难，因此，目前几乎没有或根本没有相关数据。本文讨论了植物的特定特征，这些特征使其成为揭示环境（自然环境因素）和细胞年龄对自发基因组突变率影响的强大模型系统。总体而言，证据表明植物可能是推进我们对可遗传突变如何以及为何产生的认识的关键生物系统。
