Paucity of novel short interspersed repetitive element (SINE) families in human DNA and isolation of a novel MER repeat.

An extensive compilation of renaturation rate data for human DNA is presented as an empirical guide for genomic hybridization studies and to document as accurately as possible the repetitive sequence content of the human genome. Approximately 15% of the genome renatures with heterogeneous rates characteristic of moderately repetitive sequences. Cross hybridization studies of this fraction with known repetitive sequences show that it is largely composed of known moderately repetitive sequences and contaminating highly repetitive sequences. These findings limit the maximum possible abundance of unidentified families of short interspersed elements (SINEs) in human DNA. Exhaustive analysis by subtractive hybridization of a small library constructed from short fragments of repetitive sequences yields few additional new SINEs, again suggesting the limited abundance of such sequences.