Why is the particle の used instead of が in phrases like 身寄りのない人 or the sentence 琵琶湖の向こう岸に虹の立つのを、麻子は見た。?
While I understand the meanings of these examples, I would have expected to find the nominative particle が. I've mostly seen this kind of pattern in dependent clauses and noun phrases. Does that have anything to do with it?
Does が have to be replaced with の in all cases like this, or would が be acceptable too? If so, is there any difference in nuance or style?