Genetic variation of blood groups in inbred lines of Leghorns, derived from a common base population

Nine inbred lines of White Leghorn chickens were developed by continued brother X sister mating over 10 generations. Initial matings were made in 1968 by selecting at random full sibs within each of two outbred lines of White Leghorns, which themselves had been selected since 1960 from a single population for high and low egg weight, respectively. A third base population for inbred lines consisted of a cross between the two selected lines. Blood types for the A, B, E, C, D, H, I, K, L and P blood group systems were obtained for individuals belonging to nine surviving inbred lines in 1977. All systems showed differences between lines attesting to the diverse genetic origin of the initial 1960 population that was based on eight different breeding flocks. Among the nine inbred lines, three were found to segregate for a single system; two lines segregated for two systems; and three lines segregated for three systems. The ninth line (no 92) was found to be polymorphic for six of the blood group loci. The results agree with the assumption that none of the blood group systems by itself showed heterozygosity in excess of expectations for neutral genes. Intraline polymorphisms were in excess of neutral gene expectations only in one line in which substantial deviation from all other lines suggests that a recent pedigree error and not single-locus heterosis may be the source of its genetic variabilit