Last spring I was approached by some Tutsis in the Diaspora to analyze their genomes. The first thing that jumped out at me is how genetically similar Tutsis were to the Maasai.
Since that time readers have suggested other datasets. One particular dataset was very rich in Sudanese ethnic groups. Generating a new PCA you can see that the Tutsi above are now distinct from the Maasai. They are genetically similar, but there are subtle differences. From what I can tell, the major difference is that the Tutsi are less Nilotic and more Bantu that the Maasai.
The admixture plot sequence below should make that clear (also see the f3 stats at the bottom of this post):