LINE-1 Elements in Structural Variation and Disease

The completion of the human genome reference sequence ushered in a new era for the study and discovery of human transposable elements. It now is undeniable that transposable elements, historically dismissed as junk DNA, have had an instrumental role in sculpting the structure and function of our genomes. In particular, l ong in terspersed e lement-1 (LINE-1 or L1) and s hort in terspersed e lements (SINEs) continue to affect our genome, and their movement can lead to sporadic cases of disease. Here, we briefly review the types of transposable elements present in the human genome and their mechanisms of mobility. We next highlight how advances in DNA sequencing and genomic technologies have enabled the discovery of novel retrotransposons in individual genomes. Finally, we discuss how L1-mediated retrotransposition events impact human genomes.