The QTL approach will quickly help the agricultural industry realize yield gains of a significant amount. The birth of technology called molecular breeding, mining of genomes using DNA markers to discover QTLs, will eventually transform the way the agricultural industry develops new varieties and ultimately improves productivity for the farmer and offers more choices to the consumer. Molecular Markers Molecular markers are genetic markers located at various points within the genome. DNA markers can simply be thought of as detected differences in the genetic information carried by two or more individuals. DNA markers serve other purposes besides QTL detection in plant research such as forensic science , paternity testing and the identification of genes responsible for genetic diseases.
Markers can be dominant or codominant.
Codominant markers, such as SSRs and RFLPs, show heterozygosity in F2 and BC1 populations. Dominant markers, such as AFLPs and SNPs, are rarely able to detect heterozygosity. RFLPs are detected by the use of restriction endonucleases on genomic DNA at specific restriction sites. Variable size DNA fragments result and are identified via Southern blotting. This marker system generates multiple bands that are generated in each amplification reaction that contains DNA of random origin.