Allozyme polymorphism is described and the mode of inheritance determined for 15 loci in Pisum sativum. The approximate position on the pea linkage map is described for 12 of these loci. The remaining three loci formed a single group that assorted independently of morphological markers on each of the seven currently recognized linkage groups. Possible cases of gene duplication are identified in the alcohol dehydrogenase and esterase enzyme systems, but in neither case was polyploidy a likely explanation for the paired loci. Nor did the arrangement of the isozyme loci on the linkage map give any indication that the pea genome is of polyploid derivation. We conclude that the "polymeric” genes that have been described in the pea are probably not homologous pairs and do not reflect a polypiold ancestr
