Detection of genetic diversity in Ocimum species using RAPD markers

Abstract

Ocimum is an important member of Lamiaceae and the genus is an important source of many essential oils and aroma chemicals in perfumery and cosmetic industries. Ocimum species are Used as pot herbs and find diverse uses in the indigenous system of medicine of many Asian and African countries, from industrial point of view. Ocimum species with oil rich in camphor, citral, geraniol, linalool, linalylacetate and methyl etc., are important and can be harnessed for successful utilization in industry. There is a variation in the production of these products among different species of Ocimum. Therefore, precise characterization of promising species and determination of genetic variation among those are felt necessary. Until recently, ever-promising species released formally are characterized based on morphological data, organic content and yield potential. These characters differ under varying environmental condition thereby nosing problem in proper identification of species. Unlike morphological markers, cytological (chromosome number, nuclear DNA content) and molecular markers (RAPD, AFLP, ISSR etc., ) are not prone to environmental influences and accurately characterize the plants portraying the extent of genetic diversity among the taxa. Of the different markers RAPD has been widely used in the last decade in species identification programme and in accessing genetic variations among different taxa at DNA level because of its cost effectiveness and simple operation without requiring prior knowledge of species DNA sequences. RAPDs reveal similar patterns of genetic diversity when compared with other markers type, can be performed more rapidly than most other methods, and can provide vital information for the development of genetic, sampling, conservation and improvement strategies. Random amplified Random amplified polymorphic DNA (RAPD) markers were employed to study the genetic relationships between six Ocimum species. Of the 80 random primers screened 10 primers resulted in 73 RAPD bands of good amplification. The data structure included a total of 100 to 1000 base pair marker levels. A dendrogram was constructed using Euclidean distances by Ward’s method. Based on the number of bands all the species were grouped into three clusters and the dendrogram maximum similarity between the Ocimum species.