Transposable elements possess the unique and useful ability to ‘jump’ in and out of genomes. It is now believed that this exceptional capacity for self excision and integration into host genomes may be a fundamental to generation of genetic diversity, and indeed, the formation of genes themselves.
The importance of transposable elements is found in their combined ability to work as a genetic pool of diversity. Transposable elements are highly mutagenic and after integration into host genomes they can sometimes undergo mutations leading to permanent domestication. Whether causing an increase or decrease in the fitness of the host organism, these domestication events can lead to changes in coding regions. Indeed, in eukaryotes, it has been discovered that transposons have repeatedly altered genomes, in many cases causing a change essential to survival of the organism along the rocky path of environmental change.
Research has found that transposons (or rather the domesticated remnants of transposons integrated into the genome) play important roles in a number of cellular functions ranging from regulation of cell proliferation and apoptosis to inactivation of the x-chromosome in female mammals. Another notable example is that transposons are responsible for somatic generation of diversity in B-cell and T-cell receptors essential for the immune system to respond to a wide variety of antigens.
The impact of transposable elements on eukaryotic genomes has lead scientists to believe that they are genetic generators and a driving force of evolution.
Primary source:
Volff, Jean-Nicolas, 2006, ‘Turning Junk into Gold: The Domestication of transposable elements and the creation of new genes in eukaryotes’ BioEssays 28:913-922.
Secondary sources
Kazazlan, HH Jr., 2004, ‘Mobile elements: drivers of genomic evolution’ Science 303:1626-1632.
