NOTE 19G: The data are for 25 genes with P_s > 10, and excluding genes that were sequenced because they were thought to have been positively selected (line 3 of Table 1 of Smith and Eyre-Walker 2002). The estimates are slightly different because Smith and Eyre-Walker use a denominator of P_s + 1 to reduce bias; Box 19.1 gives the simpler formula with P_s in the denominator.