COMPLETE SEQUENCE OF THE 43-KB HUMAN RIBOSOMAL DNA REPEAT - ANALYSIS OF THE INTERGENIC SPACER

We have sequenced the remaining 12.4 kb of the 30-kb human ribosomal D NA intergenic spacer (IGS), which allows us to piece together both a c omplete IGS and a 43-kb rDNA unit. The sequence of the complete IGS re veals a collection of sequence motifs that can be correlated with func tions known or expected to reside in the rDNA repeat: modulation of tr anscription, recombination initiation of DNA replication, and chromoso mal organization. Finally, we find that IGS accumulates variation at a much higher rate than the transcribed regions. This finding leads us to correlate sequence character with types of mutation and sequence co ntext with rate of mutation. (C) 1995 Academic Press, Inc.