北が上という常識は、実は北半球の国の人々が無意識に持っている差別の表れかもしれない。 (source: line 10-11)
My main issue are the parts in italic and bold. I understand the sentence as follows:
Concerning the common practice to call the north "up", to be honest the people of the northern hemisphere might appear to unconsciously be holding discrimination.
From a syntactical perspective though, I can't get through the sentence.
I would say that 北が上という常識は and 表れかもしれない are linked on one and the same syntactical level:
Concerning the common practice to call the north "up", it might appear.
In this case, I could interpret the bold の kind of like the の in a cleft sentence like here. But this concept was explained to me only very recently, hasn't really appeared before in my textbook and I don't think that I have a good grasp of it yet.
I don't really have an idea how else to interpret this の right now. The phrase 実は北半球の国の人々が無意識に持っている差別の is not really archetypical in its form. It's subject is 北半球の国の人々が, but this isn't connected to an intransitive verb, and the only verb that is there is 持つ which is transitive, but that one in turn isn't connected to a direct object, at least not through traditional means via a particle preceding the only potential direct object 差別.
That's why the only way out is filling the empty slot for the predicative with a presumably elliptic copula: "Concerning the common practice to call the north up, it might appear that it (corresponding to の, cleft sentence) is (corresponding the elliptic copula) discrimination which the people of the northern hemisphere are holding.
seems to be the subject in this clause/phrase which is embedded into 北が上という常識は...表れかもしれない, but it lacks a predicative. The whole phrase also isn't connected to a transitive verb and object or an intransitive verb. I could extrapolate the ellipsis of a copula "Concerning the common practice to call the north "up", it might appear (that) it is discrimination which the people of the northern hemisphere are holding."
Or an even more literal approach, trying to mimic the chain of attributes/attribute-like-phrases the Japanese sentence forms (in my opinion):
Concerning the common practice to call the north "up", it might appear it is people of the northern hemisphere holding discrimination.