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. Author manuscript; available in PMC: 2015 Apr 1.
Published in final edited form as: J Exp Zool B Mol Dev Evol. 2014 Jan 24;322(6):438–463. doi: 10.1002/jez.b.22558

Figure 1. Immunoglobulin heavy chain genome organization in Latimeria menadoensis.

Figure 1

Overlapping BAC clones encompassing the immunoglobulin heavy chain loci of L. menadoensis were isolated and sequenced. Locus 1, designated IgW1 (BAC clones 58E24 and 189I9; GenBank JX848736.1) contains 19 constant region exons (A), whereas locus 2, designated IgW2 (BAC clones 130A21 and 206D14; GenBank JX840472) encodes 16 constant region exons (B). Both IgH loci are comparatively large and organized in a different pattern in which V and D segments are in close (∼190 bp) V-D linkage and contain consensus RSSs. The respective genes appear to be most similar in overall sequence relatedness to IgW from the African lungfish and cartilaginous fishes. Both IgW isotypes encode a secretory tail at the end of the first seven C domains and possess two transmembrane exons at the end of last C domain. A separate BAC clone, 217L16, was identified in the same large restriction fingerprint set as were the clones encompassing the IgW2 locus (Supp. Fig. 1); however, it contains only VH and DH segments; no JH segments or CH domains were identified.