A comparative study of vicilin genes in Lens: negative evidence of concerted evolution.

Genes for vicilin, a component of legume seed storage proteins, have been identified in the cultivated lentil (Lens culinaris ssp. culinaris) and in wild species of the genus Lens. Five different types of vicilin sequences (designated A-E) have been identified in each lentil individual. The different types of sequences, and some possible variants of them (also present in each individual) are part of the vicilin family of genes. Type D sequences have the characteristics of nonprocessed pseudogenes. Comparison of nucleotide sequences indicates that lentil vicilin sequences are similar to vicilin sequences of other legume species, in particular to those of the tribe Vicieae, in which the genes Lens is included. Sequence comparison and distance and parsimony trees indicated that two groups or subfamilies of sequences, including, respectively, types A, B, and E (47 kDa vicilins) and types C and D (50 kDa), can be distinguished in lentil and other Vicieae species, and that in the Vicieae species there is no evidence of concerted evolution among the vicilin sequences of different gene subfamilies or sequences groups, as has been suggested for other legume species.