On the genomics of immunoglobulins in the gray, short-tailed opossum Monodelphis domestica

Wang, X., Olp, J. J., and Miller, R. D.

Abstract:
Annotated maps of the IGH, IGK, and IGL loci in the gray, short-tailed opossum Monodelphis domestica were generated from analyses of the available whole genome sequence for this species. Analyses of their content and organization confirmed a number of previous conclusions based on characterization of cDNAs encoding opossum immunoglobulin heavy and light chains and limited genomic analysis, including: i) the predominance of a single IGHV subgroup and clan; ii) the presence of a single IgG subclass; iii) the apparent absence of an IgD; and iv) the general organization and V gene complexity of the IGK and IGL light chain loci. In addition several unexpected discoveries were made including the presence of a partial V to D, germ-line joined IGHV segment, the first germline joined Ig V gene to be found in a mammal. In addition was the presence of a larger number of IGKV subgroups than had been previously identified. With this report, annotated maps of the Major Histocompatibility Complex, T cell receptor, and immunoglobulin loci have been completed for M. domestica, the only non-eutherian mammalian species for which this has been accomplished, strengthening the utility of this species as a model organism.