Mortality patterns In Drosophila buzzatii lines selected for wing length and developmental time.

SOTO I.; SOTO E.; CARREIRA V.; HASSON E.

DROSOPHILA INFORMATION SERVICE

University of Oklahoma

Lugar: Norman, Oklahoma; Año: 2005 vol. 88 p. 38 - 42

0070-7333

Intrinsic mortality patterns become evident when the external mortality factors are removed asin laboratory rearing conditions. Mortality can be affected directly or indirectly by selection regimes (e.g., Foley and Luckinbill, 2001). Besides, genetic correlations among traits are a central feature in quantitative genetics and also provide a parameter to measure indirect responses to selection in other traits, sharing genes with the true target of selection (Roff, 1996). This approach is fruitful in experiments aimed to address indirect effects of artificial selection.In the present study, we investigated the intrinsic mortality patterns in Drosophila buzzatiilines selected for wing length (WL) and developmental time (DT) (Cortese et al., 2002). These lines were previously selected for body size and developmental time, two traits involved in a trade off. Three sets of lines were selected for reduced developmental time, the first was also selected for shortened wing length (S lines), i.e., in the same direction of the trade off, the second was selected for increased wing length, i.e., in the opposite direction of the trade off (L lines), and finally F lines were not selected for wing length. In response to selection, the lines have dramatically diverged for both traits (Cortese et al., 2002), with S lines showing the strongest response. However, no response was observed for developmental time in L lines, whereas wing length in F lines, did not diverge from the control. These results are consistent with the hypothesis that both traits are related in a trade-off (Cortese et al., 2002) and now we evaluate the indirect effect of artificial selection on mortality. All selection lines were compared for age-specific mortality rate at 25°C in order to test whether or not they responded to selection on either body size or developmental time.