ABSTRACT
This chapter provides an overview of gene amplification as a mechanism of herbicide resistance and discusses the scope of use of molecular cytogenetic tools in weed science. Gene amplification conferring resistance to xenobiotics has been documented extensively in arthropods and eukaryotic cancer cells. Gene amplification essentially results in a selective increase in the number of copies of a gene, more likely without the proportional increase of other genes in a given genome. In the past, cytological procedures were extensively used for structural and functional analyses of chromosomes, primarily to detect chromosomes during cell division. Molecular cytogenetic techniques such as fluorescence in situ hybridization (FISH), and high resolution FISH on stretched DNA (fiber-FISH) have been developed to visualize individual genes and small DNA elements on chromosomes. applications of molecular cytogenetic techniques such as FISH and fiber-FISH have been valuable to understand the possible basis of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene amplification resulting in evolution of glyphosate resistance in weed species.
