Theory 03/Molecular/DNA duplexes
Specificity Is Mismatch Against Length
The claim
Hybridisation specificity is set by the ratio of mismatch destabilisation to duplex length, so long probes cannot distinguish a single mismatch.
01Mechanism
A single mismatch costs a fixed energy while the duplex gains energy per base pair; the ratio determines whether the difference survives.
02Prediction
Specificity should fall as length rises.
03Refutation
Specificity independent of length would remove the ratio.