In general, race in Cyteen seemed to be of absolutely minimal importance. Surface physical differences deteriorated (or evolved) into genetic ones: the most blatant division within Resuene society is the dichotomy of CIT and azi. However, I find myself wondering if that division is not just a displacement of race issues. The azi certainly seem to be the inferior members of this hierarchical structure. Although they have an important function within the society and do not seem to mind their lower status, they are forced to be servants of the upper strata of CIT's. The most constant reminder of this is Caitlin and Florian's inability (or refusal) to call Ari anything but "Sera," an honorary term.
There is also a degree of segregation within the Resuene world: the azi all live down in the "Town," in barracks separate from the CIT's whom they serve. Unless the azi have been chosen to be special servants for a CIT, they live within this segregated world.
Of course, there is another degree of segregation within the azi world--the division of them into alphabetical and intellectual classes. This division, strikingly similar to Brave New World, offers up another look into segregation within Cyteen. Maybe it all just ties into what the Oankali think--humans are inherently hierarchical... :)