Short interspersed elements (SINEs) are one of the two
most prolific mobile genomic elements in most of the
higher eukaryotes. Although their biology is still not
thoroughly understood, unusual life cycle of these simple
elements amplified as genomic parasites makes their
evolution unique in many ways. In contrast to most genetic
elements including other transposons, SINEs emerged
de novo many times in evolution from available molecules
(for example, tRNA).