In science, the prairie voles are ideal models for studying the regulatory mechanisms of social behavior in humans. The utility of the prairie vole as a biology model can be further enhanced by characterization of the genes encoding components of the immune system. Here, we report the genomic organization of the prairie vole immunoglobulin heavy and light chain genes. The prairie vole IgH locus on chromosome 1 spans over 1600 kb, and consists of at least 79 V H segments (28 potentially functional genes, 2 ORFs and 49 pseudogenes), 7 D H segments, 4 J H segments, four constant region genes (μ, γ, ɛ, and α), and two transmembrane regions of δ gene. The Igκ locus, found on three scaffolds (JH996430, JH996605 and JH996566), contains a totle of 124 V κ segments (47 potentially functional genes, 1 ORF and 76 pseudogenes), 5 J κ segments and a single C κ gene. Two different transcriptional orientations were determined for these V κ gene segments. In contrast, the Igλ locus on scaffold JH996473 and JH996489 includes 21 V λ gene segments (14 potentially functional genes, 1 ORF and 6 pseudogenes), all with the same transcriptional polarity as the downstream J λ -C λ cluster. Phylogenetic analysis and sequence alignments suggested the prairie vole's large germline V H , V κ and V λ gene segments appear to form limited gene families. Therefore, this species may generate antibody diversity via a gene conversion-like mechanism associated with its pseudogene reserves.
