Intra Specific Genetic Diversity Studies on Calotropis gigantea (L) R. Br. - Using RAPD Markers
T. Amutha Priya, V. Manimekalai, P. Ravichandran
Calotropis gigantea (L.) (Asclepiadaceae) is an important medicinal plant which exhibits variations in flower color, morphology and anatomy. Taxonomists treat these variants as two different forms due to contrasting floral features. Hence, a molecular marker based study using random amplified polymorphic DNA (RAPD) was carried out to ascertain the origin of morphological variations as well as to check whether the floral variation is due to phenotypic or genotypic factor. Further the study was aimed to assess the genetic diversity of these two forms collected from ten different accessions. Genomic DNA was isolated and purified from flower petals using the procedure described by Jobes et al., with minor modifications. The DNA content was quantified and purity was checked using Spectrophotometer. Twenty decamer random operon primers were used to amplify the DNA and RAPD-PCR was done. High level of genetic similarity was observed between the white and pink form accessions. Ten random primers, each with 10 bases generated a total of 16 polymorphic bands out of 209 total bands. In addition to the morphological variations a significant level (16 %) of polymorphism of was observed. Overall genetic similarity based on 10 random primers was 84 %. Cluster analysis was carried out based on UPGMA Jaccard coefficient. The results reveal relatively a rich source of genetic diversity of the selected variants. The observed variation and polymorphism among the morphological forms deemed to be worth for conservation of C. gigantea. The molecular variations and data obtained from these two forms can be of taxonomic importance. Further analysis involving ISSR or mini/micro satellite markers is required to confirm the results obtained.
T. Amutha Priya, V. Manimekalai, P. Ravichandran. Intra Specific Genetic Diversity Studies on Calotropis gigantea (L) R. Br. - Using RAPD Markers. European Journal of Biotechnology and Bioscience, Volume 3, Issue 5, 2015, Pages 07-09