certainly to the participants, there's a perceptible racial difference between the Sudanese Arabs and Darfur non-Arabs being massacred.  Within Sudan, Ethiopia, and Somalia, apparently, there's more racial-genetic variation than in most of the rest of the world put together.  From remnants of the Ituri-Pygmy 'old people' to the tall lighter Iman-type to compact Ethiopians and a variety of Bantus, apparently there's  greater genetic differences than there are between all other groups of humans.  The genetic literature is controversial to be sure, but I read this in a series of articles debunking 'race' as a simple genetic category.  Africa definitely has more variation than even the differences from Australian Aborigines and Polynesian Islanders to Caucasian-Americans and native Americans. 

But in the Darfur conflict (as in Rwanda) surface ethnic or alleged racial categories mask some much deeper antagonisms and socio-economic stresses which led to violent conflict.