A phylogenetic analysis of the genus Carica L. (Caricaceae) based on restriction fragment length variation in a cpDNA intergenic spacer region

The phylogenetic relationships among twelve wild and cultivated species of Carica (Caricaceae) were analyzed using restriction fragment length variation in a 3.2-kb PCR amplified intergenic spacer region of the chloroplast DNA. A total of 138 fragments representing 137 restriction sites accounting for 5.8% of the amplified region were examined. Both parsimony and neighbor joining cluster analyses confirmed the close association among South American wild Carica species. However, cpDNA data did not support the traditional monophyly hypothesis for the evolution of Carica. Further, cpDNA analyses showed two basic evolutionary lineages within the genus Carica, one defined by cultivated C. papaya and another consisting of the remaining wild species from South America in a well resolved but poorly supported monophyletic assemblage. This evolutionary split in Carica strongly suggests that C. papaya diverged from the rest of the species early in the evolution of the genus and evolved in isolation, probably in Central America.