Transposons as natural genetic engineers of genome mutation, evolution, and speciation

Repetitive DNA sequences that form a large portion of higher eukaryotic genome and can change positions within the genome are known as transposons. The movement of these genetically mobile elements occurs through cut and paste mechanism and is guided by enzymes. Transposable elements are considered as DNA transfer vehicles as they are capable of introducing a new sequence of DNA into the genome of an organism. Moreover, their utilization in the development of transgenic lines and in process of insertional mutagenesis has been observed in certain plants and animals as they can move independently of the host system and hence act as an important tool to develop mutants. In addition, the study of the evolution process in particular species requires the knowledge at both phenotypic and molecular level so to properly understand genetic diversity and gene flow at species level. Transposable elements are capable of affecting genome evolution by promoting recombination and transferring genes to new locations. Coevolution of transposons together with plant genome had led to overcome unfavorable environmental conditions or process of hybridization and polyploidy. This chapter deals with the role of transposons in evolution and species diversity.