I think you are talking about something known as hitchhiking mutations. Suppose an organism develops two mutations A and B, which lie close together in the chromosome. A is beneficial and B is neutral. When the chromosome is copied during reproduction, the copy will contain both A and B (because they are nearby). This copy will have an overall advantage because of the presence of A, and will spread in the population.
https://en.wikipedia.org/wiki/Genetic_hitchhiking
But the question remains: who put these genes near each other, so that something would evolve without being naturally selected just because its gene was near another gene?
What is the likeness of a gene near a gene that's "evolving" to be important somehow in the future of the evolution of that species?
No one did. That's not how evolution works. There is no plan, and no one decided how it would work in the future. Your second question makes me think that you're thinking of evolution as "progress", that everything is evolving towards something. It is not. That is, you're asking, given an adaption, what is the likelihood of those genes existing? But that's backwards; the genes caused the outcome.
You're trying to insert purpose or intent into what is essentially accident. Most -- almost all -- changes like these either never have lasting consequences or are eventually undone. They are insignificant, and may not even have expression, unless and until they become significant because of subsequent changes.
You can insert supernatural interference into the process -- there's nothing but the principle of parsimony (Occam's razor) preventing that -- but you can't require it in order for things to work the way they apparently do/did work.
