SINES

·         SINE’s, Short INterspersed Elements, are, as the name suggests, short DNA sequences. They are genetic elements with the ability to replicate themselves in the genome of a host cell. These elements are reverse-transcripted molecules of RNA who were transcripted from tRNA, a reaction that is catalyzed by RNA polymerase III. But these elements cannot produce the polymerase due to their short size and therefore are dependent of other elements of transpositions present in the host cell.

·         SINE’s are retrotransposions without LTR group (Non-long terminal repeat). LTR’s are used by virus to insert their genomic sequences in to the host genome and since these elements do not poses these terminal, they must associate with LINE’s.

·         Retrotransposons without LTR have 3 subtypes: LINE’s, SINE’s and Composite SINE Transposons. While LINE’s have the ability to perform all the functions required to retrotranposition, SINE’s do not have such capability and, therefore, link themselves with LINE’s. As for Composite SINE Transposons, two SINE’s connect to each other to flank and mobilize an intervening single copy DNA sequence.