Randomly Amplifi ed Polymorphic DNA (RAPD) and Derived Techniques

Abstract

Understanding biology and genetics at molecular level has become very important for dissection and manipulation of genome architecture for addressing evolutionary and taxonomic questions. Knowledge of genetic variation and genetic relationship among genotypes is an important consideration for classifi cation, utilization of germplasm resources, and breeding. Molecular markers have contributed signifi cantly in this respect and have been widely used in plant science in a number of ways, including genetic fi ngerprinting, diagnostics, identifi cation of duplicates and selecting core collections, determination of genetic distances, genome analysis, developing molecular maps, and identifi cation of markers associated with desirable breeding traits. The application of molecular markers largely depends on the type of markers employed, distribution of markers in the genome, type of loci they amplify, level of polymorphism, and reproducibility of products. Among many DNA markers available, random amplifi ed polymorphic DNA (RAPD) is the simplest and cost-effective and can be performed in a moderate laboratory for most of its applications. In addition RAPDs can touch much of the genome and has the advantage that no prior knowledge of the genome under research is necessary. The recent improvements in the RAPD technique like AP-PCR, SCAR, DAF, SRAP, CAPS, RAMPO, and RAHM can complement the shortcomings of RAPDs and have enhanced the utility of this simple technique for specific applications. Simple protocols for these techniques are presented.