Figure 1. Evolutionary and structural characteristics of YF1*7.1.

(A) The evolutionary tree reveals that YF1 isoforms are closely related to chicken MHC-BF2 variants and classical mammalian as well as non-mammalian (frog, nurse shark) class I heavy chains (red box) but are also similar to mammalian MR1 chains and human ZAG. YF1 heavy chains are, however, only distantly related to chicken and mammalian CD1 molecules as well as to EPCR. The designations of the molecules are given in the Accession Numbers section. The tree is drawn to scale, with branch lengths equivalent to evolutionary distances in the units of the number of amino acid substitutions per site. (B) Ribbon diagram of YF1*7.1 non-covalently associated with β₂m (orange), as seen along the binding groove. A ligand has been omitted for clarity.