Measuring selection in human populations using the growth rate per generation

TitleMeasuring selection in human populations using the growth rate per generation
Publication TypeJournal Article
Year of Publication2016
AuthorsEwbank, Douglas C.
JournalPhilosophical Transactions of the Royal Society of London B: Biological Sciences
Type of Article10.1098/rstb.2015.0148
Accession NumberPMID: 27022075
AbstractEstimates 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.