MOLECULAR-CLONING OF MAJOR HISTOCOMPATIBILITY COMPLEX CLASS-II B-GENECDNA FROM THE BENGALESE FINCH LONCHURA-STRIATA

The only avian major histocompatibility complex (Mhc) genes thus far i dentified are from species of the relatively small order of Galliforme s, while by far the largest order of Passeriformes (songbirds), contai ning some 60% of extant bird species, has not been studied at all in t his regard. The Galliformes emerged more than 55 million years (my) ag o, the Passeriformes some 25 my ago. Because of the potential for the use of Mhc genes as markers in the study of songbird populations, an a ttempt was made to clone class Il B genes of a passeriform species, th e Bengalese finch Lonchura striata acuticauda. Using a set of primers designed on the basis of known sequences, a probe corresponding to par t of exon II was obtained by the polymerase chain reaction. The probe was then used to screen a Bengalese finch cDNA library and to isolate and sequence two nearly full-length clones. The sequences reveal the p resence of one presumably functional class II B locus in this bird spe cies.