Table 1. Estimates of average dominance.

hR	hM	Trait	Method Note	Analyzed	Species	Reference
0.029	—	Viability	MAa	Excluded	Drosophila melanogaster	Garcia-Dorado and Caballero (2000)
0.10	—
0.2	—
0.328	—	Viability	MA	Included		Chavarrias et al. (2001)
−0.03	—	Early ♀ fec.	MAb	Included		Houle et al. (1997)
0.12	—	Late ♀ fec.
0.37	—	♂ longevity
0.26	—	♀ longevity
−0.07	—	♂ mating ability
0.12	—	Weighted mean
0.16	0.51	Viability	TE	Included		Fry and Nuzhdin (2003)
0.01	0.45	Viability	P-elem.	Excluded		Mackay et al. (1992)
0.21	—	Viability	MAc	Included		Simmons and Crow (1977)
0.29	—	Viability	MAc	Included
0.40	—	Viability	MAc	Included
0.49	—	Viability	MAc	Included
0.21	—	Viability	MAc	Included
0.21	—	Viability	MAc	Included
0.40	—	Viability	MAc	Included
0.133	0.195	Growth rate	SM	Included	Saccharomyces cerevisiae	Szafraniec et al. (2003)
0.64	—	Productivity	MA	Included	Caenorhabditis elegans	Vassilieva et al. (2000)
0.05	—	Surviv. to mat.
−0.10	—	Longevity
0.55	—	Intrinsic rate incr.
0.48	—	Convergence rate
0.69	—	Generation rate
−0.508	0.12	Productivity	EMSd	Included		Peters et al. (2003)
−0.508	0.08	Relative fitness

h_M is given by E(s_het)/E(s_hom) and h_R by Cov(s_het,s_hom)/Var(s_hom), where s_het and s_hom are the distributions of the heterozygous and homozygous fitness effects of mutations, respectively. The MA method refers to mutation accumulation of experiments that produce lines with unknown numbers of spontaneous mutations. EMS represents the same method but with mutagen-induced mutations. TE represents transposable elements. P-elem represents for P elements and SM represents the study of lines carrying exactly one single mutation. Different proxy for fitness are used in the experiments (viability, productivity, growth rate, indicated in the Trait column).

^aAlthough historically important, Ohnishi estimates present several problems as explained in Garcia-Dorado and Caballero (2000). Originally, h_R values were estimated to be low and inconsistent between crossing schemes (0.1 in coupling crosses and 0.029 in repulsion crosses). The reanalysis in Garcia-Dorado and Caballero (2000) of the same data yields a much higher value (0.2). Given all these uncertainties and the fact that other Drosophila estimates are available, we excluded this data set from our analysis.

^bThe weighted mean (0.12) given in the table is simply an average over traits given in Houle et al. (1997). We did not include it in our composite estimate of average dominance.

^cSimmons and Crow (1977) report recalculated values of h_R for different Mukai’s experiments.

^dIn this experiment, overdominance was observed in several sublines. The overall pattern [Figure 3 in Peters et al (2003)] was strikingly similar to what our model would predict away from the optimum (h_R ≈ 0.5 and presence of overdominance, Figure 5, right) although h_M was lower (≈ 0.1). Note that the h_R estimate given in the article (0.02) is mistaken (A. Peters, personal communication).