Abstract
Detection and analysis of genetic variation can help us to understand the molecular basis of various biological phenomena in plant origin. DNA based marker techniques such as RFLP (Restriction Fragment Length Polymorphism), RAPD (Random Amplified Polymorphic DNA), SSR (Simple Sequence Repeats) and AFLP (Amplified Fragment Length Polymorphism) are routinely being used in ecological, evolutionary, taxonomical, phylogenic and genetic studies of plant sciences. Now a day, a new class of advanced combined techniques has emerged, which is derived from earlier basic techniques. The newer methods also include modifications in the methodology of basic techniques. So it increases the sensitivity and resolution to detect genetic discontinuity and uniqueness. The novel marker techniques also make use of newer class of DNA elements like retrotransposons, mitochondrial and chloroplast based microsatellites, thus revealing genetic variation through increased genome coverage. Some techniques such as RAPD and AFLP are also being applied to cDNA based templates to study patterns of gene expression and uncover the genetic basis of biological responses. Genetic or DNA based markers have their applications in fingerprinting genotypes, determining the seed purity and in phylogenetic analysis by which the conservation of the plant can be made easy. A review details about techniques used in identification of markers and their applicability in plant origin.
