Table 2.

Newborn IgM VH regions predominantly use only the DH1 gene. The aligned IgM cDNA clones from Figure 2 were analyzed for DH gene usage by comparison to the horn shark genomic DH genes (Accession #X13447 [33]). The DH gene portion that exactly matches the horn shark is underlined and italicized nucleotides indicate non-templated GC nucleotide additions. Clones that could not be conclusively identified as either DH gene are indicated by (?). CDR3 identical in sequence to both DH genes are indicated by (D1/D2). Clones 22E and 36E excluded due their non-productive rearrangement.

	Horn shark X13447	DH1 GGTACAGCAGTGGGT	DH2 ATATCTGGGTG	D1 GTAVG	D2 ISGW
I	54S	GTGGGTACTGGT		VGTG
	30E	AGCCACGGGGAGAGGAGCCAGAGCCACTGTGGCTATCTT (D1/D2)		SHGERSQSHCGYL
II	1E	CAACTACAGGACTGGGATGATCCA		QLQDWDDP
	72S	GACGACAGTGGGGGGTCTCCC	ATACTGGGTCCGACCTACTAT	DDSGGSP	ILGPTYY
	35S		GACGGAGTGATACTGGGA		DGVILG
	14E	GACTACAGTG	CCTGGGATACCATTGGT	DYS	AWDTIG
III	17S		ACAACAAACTCTCTGGGT		TTNSLG
	6E		ACAATATTCGGT		TIFG
	57S	ACTACTTTCGGT (?)		TTFG
IV	55E		AGGGGGGGGGACTGGGGTAGGTTCGCT		RGGDWGRFA
	26E	AAGACCCACCTACAGTCTATA	CTGGGGTCCTTCGCT	KTHLQSI	LGSFA
	15S	GCCTCAGTGGAGCGGGAATTCGCT		ASVEREFA
	24S	GATGGTGGGGTAGGGGAATTCGCT (D1/D2)		DGGVGEFA
	46S	AGCAGTGGGTACGAATTCGCT		SSGYEFA
	29S	GTCAGGGGGGAGGCGGTT (?)		VRGEAV
	73S	GACACAGTAGGGGGAGCG		DTVGGA
V	2S	ACAGAAAGTGGG	GGGGGTGGGGCCGGT	TESG	GGGAG
	49S	ACAGATATCAGTGGCCGGGTAGCCGGT		TDISGRVAG
	M92851	ACAAGACGCATGAGTGGGTATGAATACT	TGGGCGGCCACTCCGGT	TRRMSGYEY	LGGHSG
	2E	ACCCGATCTACGGCGCCCCTTTGT (?)		TRSTAPLC
	50S	ACAGGGGGGTACTTGGGT (D1/D2)		TLG
	47S	ACAGTGGGCGGT		TVGG
	21S	ACTACAGTGGGT		TTVG
	27S	ACAGACAGTGGG		TDSG