Use of PCR-RFLP on chloroplast DNA to investigate phylogenetic relationships in the genus Phaseolus
1998
Vekemans, X. | Hardy, O. | Berken, B. (Universite libre de Bruxelles (Belgium). Lab. de genetique et d'ecologie vegetales)
Phylogenetic relationships among 74 accessions belonging to six species of Phaseolus are investigated using variation in chloroplast DNA assessed according to a PCR-RFLP protocol. Three fragments of chloroplast DNA are amplified using universal primers, and then digested with 10 restriction enzymes. Thirty-six haplotypes are identified on the basis of the polymorphism in fragment number and size. Three main phylogenetic groups, strongly supported through bootstrap analysis, are identified: (1) accessions from Phaseolus lunatus and Phaseolus xolocotzii; (2) accessions from Phaseolus glabellus; (3) accessions from Phaseolus vulgaris, Phaseolus polyanthus and Phaseolus coccineus. Within the third group, accessions of Phaseolus coccineus are scattered along the phylogenetic tree, which provides some evidence that coccineus accessions are paraphyletic with respect to Phaseolus vulgaris and Phaseolus polyanthus. An analysis of molecular variance applied on four species shows that they are significantly differentiated with 79 per cent of molecular variance among species and 21 per cent within species. The results agree with previous investigations on chloroplast DNA variation in the genus Phaseolus, and suggest that PCR-RFLP methods, which are technically less labour-intensive than previous methods, are of great value for phylogenetic investigations at the generic level
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