(long interspersed element)
Any of a class of dispersed moderately repetitive DNA found in eukaryotes, consisting of numerous copies of relatively long (generally 6–8 kb) sequences scattered throughout the genome. LINEs are retrotransposons and can spread by reverse transcription: an RNA transcript is formed, then a DNA copy of this, which subsequently undergoes insertion into the genome. An example found in humans and other mammals is the L1 element. This is 6 kb long, representing up to 21% of the total human DNA, has 50 000 copies in the human genome, and contains two large coding regions plus noncoding flanking sequences. One of these encodes both an endonuclease and a reverse transcriptase.