Table 1.

Comparison of various features of class II genes and their protein products in jawed vertebrates

	Cartilaginous fish classical	Gar DA/DB	Gar DE	Teleost fish DA	Teleost fish DB	Teleost fish DE	Tetrapods classical	Mammals DO	Tetrapods DM
Located at Mhc	+a	(+) b	(+) b	―	―	+	+	+	+
Linked with classical-type class I	+a	+	+	―	―	―	+	+	+
Classical-type polymorphism	+a			+	―	―	+	―	―
Expression	+a			high	low-med	low	high	med	med
Peptide-binding residues c	+	(+) d	(+)	+	(―)	(―)	+	(―)	―
CD4-binding βS144, βE162	―		+	+	+ /― e	+	+	+	―
Endosomal sorting motif f	―			―	+ /― e	―	―	―	+
αW43	―	―	―	―	+ /― e	―	+	+	―
Amino acid at α125	G	N	D	G	HNDKG	D	NK	ND	N

Features of class II genes and those of their protein products are compared in the upper four and in the lower five rows, respectively. Details for expression and polymorphism are described in Additional file 8: Text S2 and Additional file 9: Text S3. Sequence comparisons are based on Figure 3, Additional file 10: Text S4 and ref. 31. Blanks indicate no information. ^a Based on ref. 35 and references cited therein; ^b Probable Mhc; ^c αN62, αN69, βH81, and βN82. Pluses show relatively high conservation, and parentheses indicate partial situations; ^d No information for the β chain; ^e Some possess these features and some do not; ^f Tyrosine-based.