Beyond ribosomal DNA: on towards the telomere.
We have sequenced and analyzed 8.3 kb of sequence adjacent and distal to the human ribosomal DNA (rDNA); this distal sequence connects to the rDNA cluster just 4 kb upstream of the first promoter and is shared among the acrocentric chromosomes and, at least in part, it is also present in other primates. The sequence differs in character from that of the rDNA intergenic spacer (IGS) in that it does not contain long stretches of either polypyrimidine or polypurine. However, just like the IGS, it contains numerous repetitive elements, including retroposed fragments of 28S rRNA and large pieces of the IGS. In addition, we show that the rDNA clusters are not interrupted by other sequences and do not recombine with this distal segment.
Gonzalez
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IL
MCP Hahnemann School of Medicine, Allegheny University of the Health Sciences, Department of Pathology, Broad and Vine, Philadelphia, PA 19102, USA. gonzalez@lansol.net
Sylvester
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JE
D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping / Q000379:methods; D002877:Chromosomes, Human; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004275:DNA, Ribosomal / Q000235:genetics*; D016208:Databases, Factual; D016521:Electrophoresis, Gel, Pulsed-Field; D006801:Humans; D011323:Primates / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D016615:Telomere / Q000235:genetics*
D004275:DNA, Ribosomal