NN theory does, to some degree, predict that the distribution of the mismatches is an important factor insofar as it affects the nearest neighbors. However, the concentration of this theory on the nearest neighbor disregards the importance of longer matching stretches. The importance of mismatch distribution and uninterrupted matches is exemplified by the stronger signal for hybridization of the InflA probe with the 21-gm target (30% of the total MFI, 2005 MFI at 45 C; 8% of the total MFI, 443 MFI at 55 C) compared to the abolished signal when using a 21-pm target. This is demonstrated in Table 2 by the InflA probe hybridizations with targets containing 14 or 16 mismatches in different distribution patterns, where long uninterrupted perfectly matching sequences favoured hybridization. The cooperativity in hybridization beyond the nearest neighbor that was noticed when two or more matching trimers neighbored each other strengthened hybridization more than when the same numbers of matching trimers were separated by mismatches. In Figure 3A (45 C), the InflA probe hybridized better with 74%12nt (10% MFI), 74%15nt (26% MFI), or 75%18nt (57% MFI) targets than with the 74%9F target, with its 9 nt+9 nt of perfect match (3% MFI). Furthermore, at the higher temperature ( Figure 3B , 55 C), the 74%18nt (37% MFI) and 74%22nt (66% MFI) targets resulted in good hybridization while the 74%12F target, with its 12 nt +12 nt perfectly matching regions, failed (3% MFI).