PT - JOURNAL ARTICLE AU - Tosi, Simonetta Landucci AU - Tosi, Roberto AU - Perramon, Arturo TI - Some Rabbit Allotypic Determinants Are Isotypes in Hare DP - 1973 Jan 01 TA - The Journal of Immunology PG - 286--289 VI - 110 IP - 1 4099 - http://www.jimmunol.org/content/110/1/286.short 4100 - http://www.jimmunol.org/content/110/1/286.full SO - J. Immunol.1973 Jan 01; 110 AB - Both a and b group rabbit allotypes, which are localized respectively on the variable region of the heavy chains and on the κ type light chains of Ig molecules, are known to be associated with multiple amino acid interchanges (1, 2). How multiple differences between alleles can accumulate during evolution is not clear. It cannot even be excluded that the structural genes for the polypeptide chains characteristic of each allotype are not truly allelic but coexist on the same chromosome. Allelism would be present at a different (regulatory) locus which would allow the expression of only one of the structural genes (3). Another hypothesis, put forward by Smith et al. (4) especially with reference to the a group allotypes, is that the sequences specifying the different allotypes may have evolved not as alleles but as gene duplications. Linked genes which diverged long before the rabbits became a species, and thus accumulated a large number of differences, might have become alleles (or pseudoalleles) in contemporary rabbits.