Files in this Data Supplement:

• Supplemental file 4 - Fig. S4A (Phylogenetic clustering in sequences bearing an HLA-B*27 footprint.)
  Zipped TIF file, 19 K.
• Supplemental file 1 - Fig. S1 (HLA-B*5703 footprint mutations.
  Zipped TIF file, 473 K.)
• Supplemental file 2 - Fig. S2 (Shannon entropy at sites of HLA-A, -B, and -Cw selection compared to sites at which no HLA selection is detected in C-clade sequences.)
  Zipped TIF file, 310 K.
• Supplemental file 3 - Fig. S3 (Effect of the addition of an HLA-B*5703 footprint on phylogenetic clustering.)
  Zipped TIF file, 292 K.
• Supplemental file 5 - Fig. S4B and C
  Zipped TIF file, 519 K.
• Supplemental file 6 - Legends to supplemental figures
  Zipped MS Word document, 5 K.