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The genomic structure of a human chromosome 22 nucleolar organizer region determined by TAR cloning
- Source :
- Scientific Reports, Vol 11, Iss 1, Pp 1-14 (2021), Scientific Reports
- Publication Year :
- 2021
- Publisher :
- Nature Portfolio, 2021.
-
Abstract
- The rDNA clusters and flanking sequences on human chromosomes 13, 14, 15, 21 and 22 represent large gaps in the current genomic assembly. The organization and the degree of divergence of the human rDNA units within an individual nucleolar organizer region (NOR) are only partially known. To address this lacuna, we previously applied transformation-associated recombination (TAR) cloning to isolate individual rDNA units from chromosome 21. That approach revealed an unexpectedly high level of heterogeneity in human rDNA, raising the possibility of corresponding variations in ribosome dynamics. We have now applied the same strategy to analyze an entire rDNA array end-to-end from a copy of chromosome 22. Sequencing of TAR isolates provided the entire NOR sequence, including proximal and distal junctions that may be involved in nucleolar function. Comparison of the newly sequenced rDNAs to reference sequence for chromosomes 22 and 21 revealed variants that are shared in human rDNA in individuals from different ethnic groups, many of them at high frequency. Analysis infers comparable intra- and inter-individual divergence of rDNA units on the same and different chromosomes, supporting the concerted evolution of rDNA units. The results provide a route to investigate further the role of rDNA variation in nucleolar formation and in the empirical associations of nucleoli with pathology.
- Subjects :
- 0301 basic medicine
Nucleolus
Molecular biology
Chromosomes, Human, Pair 22
Science
Biology
Ribosome
DNA, Ribosomal
Article
03 medical and health sciences
Genetic Heterogeneity
0302 clinical medicine
Genetics
Nucleolus Organizer Region
Humans
Cloning, Molecular
Cloning
Multidisciplinary
Concerted evolution
Genome, Human
Molecular Sequence Annotation
Genomics
Nucleolar Organizer Region
030104 developmental biology
Medicine
Chromosome 21
Chromosome 22
Ribosomes
030217 neurology & neurosurgery
Cell Nucleolus
Reference genome
Subjects
Details
- Language :
- English
- ISSN :
- 20452322
- Volume :
- 11
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- Scientific Reports
- Accession number :
- edsair.doi.dedup.....74aa4e4bc616c2d34879dcf0fb8d8ebb