At present, the source of lncRNA is not very clear. Ponting et al.10 thought that lncRNA may have arisen in the following ways: mutations in the open reading frames (ORFs) of protein-coding genes during early evolution, leading to structural disruption and then to lncRNA; chromatin recombination resulting in two originally distant non-transcript fragments coming together to produce lncRNA; duplication of non-coding genes formed by reverse transcription transposition; repetition of a certain sequence, resulting in lncRNA with adjacent repeat sequences; and DNA sequence insertion by a transposable element to produce functional lncRNA. Although many lncRNAs have no common origin, they play similar roles in the regulation of gene expression, and their most important function may be epigenetic regulation of the genome.10