In Othello, race is predominant from the very beginning. Even without meeting Othello, the audience becomes aware that Othello, the "old black ram is tupping your white ewe," (I.i.90) allowing Iago to begin weaving his trap, convincing Venetians that Othello is not to be trusted on the grounds of his race and, in fact, possesses animalistic or base characteristics. Iago uses Roderigo for his own purposes and wastes no time in setting up Othello so he can "serve my turn upon him"(42), and even Brabantio, Desdemona's father, who has invited Othello into his home many times, begins to wonder if Othello has used his "chains of magic" (I.ii.65) on Desdemona. Othello would have been considered quite exotic and, by his own admittance, Desdemona is fascinated by his stories from Africa, adding to the suggestion that his skin color is relevant to his behavior.
On discussing Desdemona's marriage, Brabantio even suggests that for her to have fallen for Othello is "against all rules of nature."(I.iii.101) Once the matter is resolved, the Duke suggests to Brabantio that Othello is "far more fair than black," (290) supporting the Venetians' beliefs and mistrust of Othello's skin color, even if the Duke's intention was simply to refer to Othello's virtuousness. It is his actions and valor that seem to raise him above what is otherwise a potential flaw.
Othello's own insecurities, despite his assertions that he is deserving, are also ultimately linked to his skin color and he is almost convinced that it is not only his jealousy but his status as a "malignant and a turban'd Turk" (V.ii.356) that renders him inferior and has contributed to his unfortunate situation. Appearance versus reality is an important theme in Othello and the fact that Othello, "the Moor" is the one to be mistrusted is ironic due to Iago's abilities to sew doubt, especially into Othello's own mind. This drives the play, reinforces the race issue as Othello tries to be good enough, and ensures that the focus is on various aspects of Othello's character, not the least of which is his misplaced trust in "honest, honest" Iago. Hence, stereotypes and society's own interpretation of Othello's worthiness make race relevant to the play.