. "12 An Experimental Test of Evolutionary Trade-Offs During Temperature Adaptation--ALBERT F. BENNETT and RICHARD E. LENSKI." In the Light of Evolution: Volume 1. Adaptation and Complex Design. Washington, DC: The National Academies Press, 2007.
The following HTML text is provided to enhance online
readability. Many aspects of typography translate only awkwardly to HTML.
Please use the page image
as the authoritative form to ensure accuracy.
In the Light of Evolution, Volume I: Adaptation and Complex Design
TABLE 12.1 Fitness at 20°C of the 20°C-Selected Lineages and Their Historical Progenitors, Each Measured Relative to the Common Ancestor
−1
−2
−3
32
1.026 ± 0.050
1.081 ± 0.026
1.022 ± 0.019
32/20
1.124 ± 0.065
1.266 ± 0.076
1.121 ± 0.024
37
0.979 ± 0.045
0.997 ± 0.034
0.897 ± 0.042
37/20
1.072 ± 0.053
1.124 ± 0.080
1.050 ± 0.045
42
0.947 ± 0.061
1.005 ± 0.039
0.992 ± 0.059
42/20
1.019 ± 0.041
1.089 ± 0.089
1.128 ± 0.057
32–42
1.018 ± 0.035
1.085 ± 0.014
1.001 ± 0.035
32–42/20
1.143 ± 0.052
1.113 ± 0.039
1.191 ± 0.042
Rows are historical selective temperature regimes; columns are lineage designations (see Fig. 12.1). Entries are mean values ± 95% confidence limits, with n = 6 replicate fitness assays for each entry.
TABLE 12.2 Change in Fitness (ΔW) at 20°C of 20°C-Selected Lines Compared with Their Historical Progenitors
−1
−2
−3
32/20 vs. 32
0.098
0.185
0.099
P = 0.006
P < 0.001
P < 0.001
37/20 vs. 37
0.093
0.128
0.154
P = 0.003
P = 0.002
P < 0.001
42/20 vs. 42
0.073
0.084
0.136
P = 0.015
P = 0.025
P = 0.001
32-42/20 vs. 32-42
0.125
0.028
0.190
P < 0.001
P = 0.056
P < 0.001
Cell entries are changes in mean fitness from Table 12.1 and P values of one-tailed t tests.
Therefore, there was a general adaptation to selective temperature in this experiment, and this adaptation was also significantly manifest in >90% of the individual lineages. The mean fitness increment is not significantly different (P = 0.14) from that of six replicate lines selected at 20°C directly from Anc (Mongold et al., 1996).
Trade-Off at 40°C
Table 12.3 gives the relative fitness, measured at 40°C, of each lineage that evolved at 20°C and its immediate progenitor. The resulting change in fitness at 40°C (ΔW) is reported in Table 12.4. Changes in fitness (ΔW) were not significantly affected by historical environment (F3,20 = 0.282, P = 0.84).
