[Genomic instability associated with human LINE-1 rétrotransposition]

LINE-1 (L1) retrotransposon accounts for approximately 17 % of the human genome. Because of the great number of identical copies, L1 can be implicated in genomic rearrangements associated with events of homologous recombination between heterologous sites. Moreover, even if the vast majority of the L1 elements are inactive, some are still able to mobilize themselves by retrotransposition. Thus, L1 is regarded as an insertional mutagenic agent. Moreover, recent works have shown that active retrotransposons were able to mobilize other sequences to generate retro-pseudogenes or to amplify other repeated sequences. Finally, L1 has been associated recently with new genomic rearrangements generated upon insertions such as large genomic deletions. L1 then can be considered as a major factor that has affected and shaped the human genome through several mechanisms.