The absence of clear selection pressure on certain RNA pairs doesn’t prove they lack function; many biological roles are subtle, context-dependent, or involve redundancy, making them difficult to detect with current methods. Freely mutating sequences could still influence genome architecture, gene regulation, or adaptation in ways not yet understood, as seen with elements like noncoding RNAs and transposable elements previously dismissed as “junk.” Additionally, these sequences may serve functions over long evolutionary or environmental time horizons, becoming critical under future conditions we cannot yet predict, underscoring the importance of not prematurely dismissing them.
I'm not suggesting that these sequences can "look forward" in time. However, consider that mutations are constantly occurring. These mutations shouldn't be dismissed as "junk" simply because they seem unnecessary now. In the future, they could become essential.
Over long evolutionary or environmental timeframes, these sequences may take on important functions, potentially becoming critical under conditions we can't currently foresee.
If such a mutation occurs, that sequence would no longer be junk. Until and unless it does happen, it's still junk. But it's silly to get hung up on the sequence, or on the word "junk", based on such a slim chance. What are you trying to prove here?
