MRC Centre for Outbreaks, Department of Infectious Disease Epidemiology, Imperial College, St Mary's Campus, Norfolk Place, London W2 1PG, United Kingdom.
Evolution. 2012 Feb;66(2):605-11. doi: 10.1111/j.1558-5646.2011.01458.x. Epub 2011 Oct 3.
It is widely accepted that the rate of evolution (substitution rate) at neutral genes is unaffected by population size fluctuations. This result has implications for the analysis of genetic data in population genetics and phylogenetics, and provides, in particular, a justification for the concept of the molecular clock. Here, we show that the substitution rate at neutral genes does depend on population size fluctuations in the presence of overlapping generations. As both population size fluctuations and overlapping generations are expected to be the norm rather than the exception in natural populations, this observation may be relevant for understanding variation in substitution rates within and between lineages.
人们普遍认为，中性基因的进化速率（替换率）不受种群大小波动的影响。这一结果对群体遗传学和系统发生学中的遗传数据分析具有重要意义，特别是为分子钟概念提供了依据。在这里，我们表明，在存在重叠世代的情况下，中性基因的替换率确实取决于种群大小波动。由于在自然种群中，种群大小波动和重叠世代预计是常态而不是例外，因此这一观察结果可能与理解谱系内和谱系间替换率变化有关。
