Variation-inducing genetic element

Biological variation is mostly due to genetic losses, duplications and translocations. Point mutations may add variation to genomes, but their contribution is completely insignificant compared to that caused by the frontloaded genetic mechanisms that are specialized in inducing variation. In GUToB Theory genetic variation is facilitated by frontloaded variation-inducing genetic elements (VIGEs). Several classes of VIGEs can be discerned based on their mechanism of action:
1) Genetic elements known as endogenous retroviruses (ERVs)
2) Genetic elements known as long terminal repeats (LTR) retrotransposons
3) Non-LTR retrotransposons (LINEs)
4) Short interspersed elements (SINEs)
5) Repetitive triplet sequences (RTS)
6) Transposons (in plants)
7) IS elements (in bacteria)
The IS element, a DNA retroposon, is the predominant VIGE observed in bacteria. Without exception, every newly discovered micro-organism contains IS elements. Variation in plants is also mediated by a class of VIGEs, commonly knowns as transposons. In eukaryota several additional classes of VIGEs are observed, including ERVs (endogenous retroviruses), LINEs and SINEs.

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