Table I.

Germline V_H genes: IgM and IgM-derived loci detected by vh probe

Subfamily	Locus	Genomic V-D-D-J Clone Accession Number	cDNA	Remarks
IgM (rearranging):
Group 1	G1	DQ857386	EU106186
Group 2	G2A	DQ192492, DQ192494	AY583357, AY594650	V1, V2 resp. may be allelesa
	G2B	DQ192493	EU106179
	ψG2C	DQ857389	ND	Pseudogeneb
Group 3	G3	DQ857384	EU106181
Group 4	G4A	Phage E2; DQ857390	EU106182
	G4C	Phage B3; DQ857388	EU106184	G4C and G4G share VH and Cμ1 but not Cμ2
	G4G	Phage B2	EU106185
	G4E	Phage S5; DQ857387	EU106182
Group 5	G5	DQ857385	M92851, EU106180
Group 6	ψG6	ND	AY609274c	VH only; pseudogene
Group 7	ψG7	EU312153	—	Pseudogened
Group 8	ψG8	EU312152	EU106187	Pseudogenee
IgM-related (germline-joined VDJ):
IgM1gj	H1gj	ND	AF327520	Prominent in neonates
IgM2gj	ψH2gj	EU312154	—	Pseudogenef

^aComplete H chains of the G2A members V1 and V2 differ by 1 bp in CDR2. These cDNA sequences carry no mutations.

^bG2C carries a one bp deletion in Cμ1 and a 13 bp deletion in Cμ2. Transcripts can be detected by RT-PCR.

^cThe cDNA contains only V_H and J_H germline sequence. No C sequence is spliced to J_H, none was found in BAC library.

^dNo cDNA found by RT-PCR (Malecek and Hsu, data not shown); stop in J gene segment.

^eLeader intron cannot be spliced out; confirmed in cDNA. J_H may be deleted; also missing in cDNA.

^fNot found in BAC library with CH3–4 probe.

ND, Not done; —, not detected.