Standard deviations are provided where applicable. Values separated by a slash in the second column for Locus 2 are the results of two independent heat shock studies. The following binding intensities were used: N1 = 0.003, N2 = 0.054, P1 = 0.010/0.037, P2 = 0.050/0.093 (Locus 1) and P0 = 0.2, P1 = 0.9, P2 = 0.3, P3 = 0.1 (Locus 2), ref. to the Results. Other model parameters were fixed at the values shown in Table 1.