Molecular Markers: An Excellent Tool for Genetic Analysis

Abstract

Commentary The exploitation of DNA polymorphisms by an ever-increasing number of molecular marker technologies has begun to have an impact on animal and plant genome research and breeding. A large number of different molecular techniques for genetic diversity analysis are available and each of them differs in its informational content. These techniques not only helped in understanding the different structure and behavior of species genome, but also revolutionized and modernized the ability to characterize genetic variation. Identification of marker linked to useful traits has been based on complete linkage maps and bulked segregation analysis. Markers are therefore used to identify traits, their inheritance and characterize germplasm. Wide range of DNA marker technologies, which require a small amount of DNA has become very useful for screening large population of segregating progenies. Presently 11 different molecular marker methods: restriction fragment length polymorphism (RFLP), random amplified polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP), inter-simple sequence repeats (ISSRs), sequence characterized regions (SCARs), sequence tag sites (STSs), cleaved amplified polymorphic sequences (CAPS), microsatellites or simple sequence repeats (SSRs), expressed sequence tags (ESTs), single nucleotide polymorphisms (SNPs), and diversity arrays technology (DArT) as well as use of the molecular marker in the present day agriculture and plant breeding programmes. Qualitative and quantitative information on diversity is an essential aspect of many fields in biology. The use of so-called molecular markers, however, facilitates all these processes, since it can accelerate the generation of new varieties and allow connection of phenotypic characters with the genomic loci responsible for them.