Random amplified polymorphic DNA variation among and within selected Ixora (Rubiaceae) populations and mutants

Abstract

Random amplified polymorphic DNA (RAPD) analysis was used to study variation among and within selected Ixora (Rubiaceae) populations and mutants. Six populations of I. congesta yielded identical banding patterns suggesting genetic uniformity of this species. However, six populations of I. coccinea varieties (three red-flowered, two yellow-flowered and one red-flowered wild-type) exhibited infraspecific differences in RAPD profiles. Small and large leaves of an atavistic mutant cultivar of I. coccinea were also subjected to RAPD analysis. An extra band was-amplified in the large leaves that was absent in small leaves, suggesting that the phenotypic alteration in this taxon is due to genetic mutation rather than epigenetic changes. Similarly, an extra band was detected in the white sectors of I. VARIEGATED compared to the green sectors, suggesting that the shoot apical meristems of this cultivar exist as a genetic chimera. DNA gel blot hybridization was performed to confirm the specificities of selected bands. Our study indicates that differences among individuals of various populations and mutants may be detected using RAPD markers.