THE IMMUNOGLOBULIN REPERTOIRE OF THE RAINBOW-TROUT (ONCORHYNCHUS-MYKISS) - DEFINITION OF 9 IGH-V FAMILIES

An Igh-V library was constructed from the head kidney cytoplasmic RNA of an 8.5-month-old non-immunized rainbow trout, Oncorhynchus mykiss, using the 5' RACE polymerase chain reaction. Six new Igh-V segments we re identified, bringing to nine the number of Igh-V families actually defined in that species. A phylogenetic analysis shows that these nine Igh-V families can be classified into three major groups. The first i ncludes the Igh-V1, Igh-V3, Igh-V4, and Igh-V7 families, and is homolo gous to the human and mouse Group m Igh-V families. The second include s the Igh-VS, Igh-V8, and Igh-V9, families and is more closely related to the Group I and Group II human and mouse Igh-V families. The third group includes the Igh-V2 and Igh-V6 families, which are not closely related to any other vertebrate Igh-V gene. Six Igh-J segments were ch aracterized. They can recombine with Igh-V segments belonging to diffe rent families and there is a high level of junctional diversity betwee n the Igh-V and Igh-J segments.