Fig. 3.

A trade-off between growth rate and mating efficiency. (A) The wild-type allele of GPA1 down-regulates genes in the mating pathway producing an expression profile intermediate to that of deletions eliminating basal signaling (ste7Δ, ste4Δ, and ste12Δ) and those not affecting signaling (far1Δ and ste2Δ). Shown are 3 independent wild-type GPA1 allele replacement strains. (B) Wild-type GPA1 allele replacement strains have a growth-rate advantage relative to the GPA1-G1406T allele strains (s_g = 0.92% ± 0.35% and −0.17% ± 0.34% for the wild-type GPA1 allele and the GPA1-G1406T allele, respectively, P < 2.6 × 10⁻⁶, t test). The points represent 3 independent measurements for each of 3 independent transformants of each GPA1 allele. (C) Wild-type GPA1 allele replacement strains have a mating disadvantage relative to the GPA1-G1406T allele strains (s_m = −27.2% ± 6.5%). MATa strains carrying each allele were mixed and allowed to compete for a limiting number of MATα cells. The mating coefficients (s_m) were calculated as the change in the natural logarithm of the ratio of the 2 alleles: s_m = ln(wild-type GPA1/GPA1-G1406T)_postmating − ln(wild-type GPA1/GPA1-G1406T)_premating.