Ewbank Douglas
Population Studies Center, University of Pennsylvania, Philadelphia, PA 19104, USA
Philos Trans R Soc Lond B Biol Sci. 2016 Apr 19;371(1692):20150148. doi: 10.1098/rstb.2015.0148.
Estimates of the speed of evolution between generations depend on the association between individual traits and a measure of fitness. The two most frequently used measures of fitness are the net reproduction rate and the 1-year growth factor implied by the fertility and mortality rates. Results based on the two lead to very different results. The reason is that the 1-year growth factor is not a measure of change between generations. Therefore, studies of changes between generations should use the amount of growth over the length of a generation. This is especially important for studies of human populations because of the long length of generation. In addition, estimates based on a single year's growth are overly sensitive to data on individuals who fail to reproduce. The effects of using a generational measure are demonstrated using data from Kenya and Ukraine. These results demonstrate that using a 1-year growth rate to measure fitness leads to estimates that understate the rate at which evolution changes the characteristics of a human population.
对代际间进化速度的估计取决于个体性状与适应度衡量指标之间的关联。最常用的两种适应度衡量指标是净繁殖率以及由生育率和死亡率所隐含的一年增长因子。基于这两者得出的结果大相径庭。原因在于一年增长因子并非代际间变化的衡量指标。因此，关于代际间变化的研究应采用一代时间跨度内的增长幅度。由于人类一代的时间跨度较长，这一点对于人类种群研究尤为重要。此外，基于单一年度增长的估计对未生育个体的数据过度敏感。利用肯尼亚和乌克兰的数据展示了采用代际衡量指标的效果。这些结果表明，使用一年增长率来衡量适应度会导致低估进化改变人类种群特征的速率的估计值。
