Enhanced heterogeneity of the LR2 segment in the human ribosomal intergenic spacer.
Human ribosomal intergenic spacer (rIGS) contains in its central part two highly homologous 2 kb repeats, LR1 and LR2. In this paper, we investigate heterogeneity of the variable LR2 segment (LR2var) in the human rIGS. More than 500 LR2var copies from ten unrelated human genomes have been cloned and sequenced. Prolonged (G)n (AG)m compound microsatellite clusters with 'n' and 'm' notions fluctuating in random manner span central parts of almost all LR2var variants. Nucleotide sequences flanking the central microsatellite clusters are represented by more than 30 structural groups, with the two major (A and B) and six minor (C-H) ones. The analysis of sequencing data let us propose that the LR2var variability can be derived by various ways, including microsatellite DNA slip-strand mispairing during replication, non-equal crossover and segmental DNA exchange between LR1var and LR2var through the mechanism of gene conversion.
Kupriyanova
N S
NS
Institute of Gene Biology, Russian Academy of Sciences, 34/5, Vavilov Street, Moscow, 119334, Russia. cuprum242@rambler.ru
Shibalev
D V
DV
Voronov
A S
AS
Ryskov
A P
AP
D001483:Base Sequence; D003001:Cloning, Molecular; D021903:DNA, Ribosomal Spacer / Q000235:genetics*; D018740:Genetic Heterogeneity; D006801:Humans; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012091:Repetitive Sequences, Nucleic Acid; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D021903:DNA, Ribosomal Spacer