In the discussion of the valence state of oxygen in reference 1 the energy of the valence state was given incorrectly as F-1P IN.

No abstract

The degree of genetic polymorphism at the DRB3 locus in the major histocompatibility complex (Mhc) of the North American bison was investigated by PCR and DNA sequence analysis. Nine different alleles were characterized in a selected sample of 20 animals. The genetic distances between alleles were as large as usually found at highly polymorphic Mhc loci in other species. A comparative analysis of the DRB3 polymorphism in bison and cattle revealed an extensive sharing of sequence motifs. The result clearly shows a transspecies persistence of DRB3 allelic lineages in the two species. Consequently a significant amount of Mhc polymorphism has been maintained through the population bottleneck that bison experienced in the late nineteenth century. An analysis of the pattern of sequence polymorphism among bison and cattle DRB3 alleles strongly suggested that interallelic recombination has contributed significantly to the generation of allelic diversity at this locus.

The discovery of additional phenotypic variability in relatively long-established systems of blood groups sometimes comes about rather suddenly after long periods of quiescence. The M-N system of man (Landsteiner and Levine, 1928) is a case in point, For a period of approximately 20 years that system was regarded for all purposes as a two-blood-factor (M and N), two-allele (LM and LN), three-phenotype (M, MN, and N) system, even though variants (Nz) of agglutinogen N were known. Then, beginning with the discovery of blood factor S (Walsh and Montgomery, 1947), the M-N-S system, as it is presently known, has become expanded into a polyphenotype system involving numerous alleles, perhaps well over 30. The F-V system of cattle was, at the time of its inception in 1943, a perfect analogue in infrahuman species of the original M-N system of man. Like M-N, it appeared as a two-blood-factor 5 (normal sheep serum); 6 (normal goat serum); 7 (normal Pronghorn antelope serum); 8 (sheep anticattle); 9 (goat anticattle); 10 (rabbit antihuman A); 11 (cattle antihuman A); 12 (cattle antibison) ; 13 (rabbit antibison) ; 14 (rabbit anticamel); 15 (see Discussion).