Polymorphism at the self-incompatibility locus in Solanaceae predates speciation

摘要: Abstract Sequences of 11 alleles the gametophytic self-incompatibility locus (S locus) from three species Solanaceae family have recently been determined. Pairwise comparisons these reveal two unexpected observations: (i) amino acid sequence similarity can be as low 40% within and (ii) some interspecific similarities are higher than intraspecific similarities. The gene genealogy clearly illustrates this unusual pattern relationships. data suggest that polymorphism at S existed prior to divergence has maintained present. In support hypothesis, number shared polymorphic sites was found exceed in simulations with independent accumulation mutations. Strictly neutral evolution is exceedingly unlikely maintain for such a long time. allele multiplicity extreme age consistent Wright's classic one-locus population genetic model self-incompatibility. Similarities between plant mammalian major histocompatibility complex discussed.