Allelic Diversity of Acetyl Coenzyme A Carboxylase / Genes Implicated in Nuclear-Cytoplasmic Conflict in the Wild and Domesticated Pea ( sp.).

Reproductive isolation is an important component of species differentiation. The plastid gene coding for the acetyl-CoA carboxylase subunit and the nuclear gene coding for the biotin carboxyl carrier protein were identified as candidate genes governing nuclear-cytoplasmic incompatibility in peas. We examined the allelic diversity in a set of 195 geographically diverse samples of both cultivated ( , ) and wild ( and ) peas. Based on deduced protein sequences, we identified 34 and 31 alleles that are partially geographically and genetically structured. The is highly variable due to insertions of tandem repeats. and have unique alleles and combinations of both genes. On the other hand, partial overlap was observed between and . Mapping of protein sequence polymorphisms to 3D structures revealed that most of the repeat and indel polymorphisms map to sequence regions that could not be modeled, consistent with this part of the protein being less constrained by requirements for precise folding than the enzymatically active domains. The results of this study are important not only from an evolutionary point of view but are also relevant for pea breeding when using more distant wild relatives.