Detection of a hypervariable DNA locus in birds by hybridization with a mouse MHC probe

The identification of broad classes of DNA probes which detect hypervariable genetic markers in different taxa is invaluable for parentage analysis in wild vertebrates. Restriction-fragment-length polymorphisms, detected by hybridization of a mouse class II major histocompatibility complex (MHC) cDNA probe to genomic DNA from red-winged blackbirds (Agelaius phoeniceus), are shown to have the genetic characteristics of a single hypervariable locus with many codominant alleles. Surveys of DNA from unrelated individuals that was cut with a single restriction enzyme (EcoRI) revealed a large number (37) of resolvable alleles with a low mean frequency (P = 0.021). When RFLP data from multiple enzymes are combined with segregation data, individual-specific haplotypes can be generated. These characteristics make this probe ideal for parentage analysis in this and other blackbird species. The many MHC probes available from mice and humans may provide a valuable source of hypervariable single-locus genetic markers, precluding the necessity of isolating species-specific probes from genomic libraries.