TY - JOUR T1 - Variability in fitness effects and the limitations of lineage selection JF - bioRxiv DO - 10.1101/107847 SP - 107847 AU - Christopher J Graves AU - Daniel M Weinreich Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/02/11/107847.abstract N2 - Natural selection is sensitive not only to the effect of a trait on total number of offspring produced but also to how a trait affects an individual’s entire lineage of descendants. Here we show how a large number of seemingly disparate evolutionary problems, including sex, evolvability, and cooperation, all share the property that fitness varies among members of a lineage. This feature makes it difficult to summarize the evolutionary fate of an allele based solely on its effects on individual reproduction. We show that attempts to average over this variability are often justified, but can sometimes cause misleading results. We then describe a number of intriguing new evolutionary phenomena that have emerged in studies that explicitly model the fate of alleles that influence long-term lineage dynamics. We conclude with prospects for generalizations of population genetics theory and discuss how this theory might be applied to the evolution of infectious diseases. ER -