Fig. 1

Response to selection. a Males from the Y1 replicate populations (circles) responded to selection by increasing negative geotaxis, while males from the Y25 replicate populations (squares) showed no significant increase. Filled symbols represent geotaxis score prior to selection and empty symbols represent geotaxis after selection. b Females from the Y1 and Y25 replicate populations showed variation in their response to male selection on the genome. Significant differences between generation 1 and 16 within a population are marked by an asterisk and based on t-tests adjusted for multiple comparisons (k = 6). Error bars represent standard errors. See methods for LS means calculation