A CLASS OF HIGHLY REPEATED DNA SEQUENCES UBIQUITOUS TO THE HUMAN GENOME

Abstract

Publisher Summary This chapter discusses a class of highly repeated DNA sequences ubiquitous to the human genome. A highly repetitive family of 300-nucleotide-long sequences has been isolated from human DNA. These sequences appear to be interspersed with single-copy DNA sequences and are characterized by a site for the restriction enzyme Alu I located 170 nucleotides from one end. The same sequence family has been found in 300-nucleotide long inverted repeated human DNA. This Alu family of sequences contains over half of the 300-nucleotide long repeated sequences and constitutes at least 3% of the human genome. This corresponds to a 300-nucleotide long sequence repeated more than 200,000 times. The Alu family appears to be interspersed throughout 30 to 60% of the human genome. The Alu family does not appear to be related to the tandemly repeated sequences which have been isolated from human DNA by restriction enzyme cleavage. These sequences may be related to repeated sequences which have been found to be interspersed throughout the hnRNA. These hnRNA sequences have a very low complexity as indicated by fingerprint analysis. The inverted repeated DNA sequences have been shown to contain the same sequences as the repeated hnRNA sequences.