Serological Differentiation of the Homozygotes and Heterozygotes in Back-Cross Birds Following a Species Cross in Columbidae

Abstract

The spp.-specific cellular antigens A, B, C, E and F of the red blood cells of C. guinea in contrast to C. livia were maintained in back-cross hybrids by back-crosses to livia and by mating the back-cross hybrids inter se. Two offspring homozygous for antigen C were used in immunological tests for specific livia substances. Reagents for the contrasting antigens of livia were prepared by absorbing the anti-livia sera with cells of back-cross homozygotes, such as CC. Possession of an antigen of guinea by the back-cross hybrids was detd. by agglutination of the cells with the specific reagents. The reagent produced by absorbing 9 antisera to livia when absorbed with cells of CC birds strongly agglutinated cells of livia and of known heterozygotes, tut did not agglutinate cells of homozygotes (CC). It was concluded that the cells of livia had an antigen, designated C1, which was antithetical to the C of guinea. Agglutination occurred at a serum dilution of 1:7680 with guinea cells due to cellular antigens common to guinea and livia and at a dilution of 1:30,720 with CC, CC1 and livia cells. 150 birds from 31 families involving only antigen C of guinea had C or C1 or both. Segregation of homozygous and heterozygous genotypes from various matings fell within genetic expectations. By methods paralleling those used in detecting C1, livia was found to have cellular substances A1, B1, E1 and F1 antithetical, resp. to A, B, E and F of guinea. When titers of 3 representative anti-livia sera of the 9 investigated were tested with appropriate absorptions for detection of the different antigens, all contained antibodies for C1 but some lacked antibodies for A1, B1, E1 or F1.