RAPD Analysis for Detection of Genetic Variability and Sex in Givotia

Givotia rottleriformis Griff. is an economically important dioecious tree species known for the softwood used in making toys. Knowledge of genetic variation in a dioecious tree species is important for devising strategies for its successful management and conservation. Studies were conducted to examine the genetic variation in Givotia plants using RAPD (random amplified polymorphic DNA) analysis and to identify molecular marker(s) linked to sex, if any. RAPD analysis was initially performed using 32 random decamer primers in DNA bulks of 5 male and 5 female plants. Out of 32 random primers tested, 24 resulted in DNA amplification of male and female plants whereas no amplification was observed with the remaining 8 primers used. Analysis of individual male and female plants with 24 random primers revealed a total of 142 amplified bands of which 86 were polymorphic accounting for an average polymorphism of 52.9%. The highest number of amplified bands (11) was generated from primer OPAL-08, 8 of which were polymorphic; the highest number of polymorphic bands (10) was generated from primer OPG-16. Cluster analysis constructed from pooled RAPD data using Jaccard’s similarity coefficient showed grouping of males and female plants into three clusters at a 70% similarity level. Twelve random primers which produced sex-specific bands in DNA bulks of males and females when tested in individual male and female plants exhibited a variable banding pattern except for primer OPT-17, which amplified a 1000-bp band in all 5 females and also in 1 male thus exhibiting partial association with sex. _____________________________________________________________________________________________________________