Definition for Short interspersed elements
From Biology Forums Dictionary
Short interspersed elements (SINEs) are highly repetitive sequences that retrotranspose into eukaryotic DNA through intermediates transcribed by RNA polymerase III (pol III). In many species, SINEs are a ubiquitously dispersed feature of the whole genome, often constituting a significant (~10%) mass fraction of total DNA. SINEs cause mutations both by their retrotransposition within genes and by unequal recombination, and are widely considered to be examples of ‘selfish’ or ‘parasitic’ DNA.