Any of a class of dispersed moderately repetitive DNA found in eukaryotes, consisting of numerous copies (>105) of relatively short (<500 bp) sequences scattered throughout the genome. SINEs are not translated into proteins, occur mostly in introns, and are nonautonomous retrotransposons, which require a reverse transcriptase from another source (probably a LINE) in order to replicate via an RNA intermediate. The most notable example in humans and other primates is the Alu family.