1. Juxta-centromeric region of human chromosome 21 is enriched for pseudogenes and gene fragments
- Author
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K. Gardiner, Sylvie Gimenez, Shelagh Boyle, Gérard Roizès, Myriam Ruault, Morgane Rolland, Albertina De Sario, and Valérie Trichet
- Subjects
DNA, Complementary ,Guanine ,Chromosomes, Human, Pair 21 ,Centromere ,Biology ,Hybrid Cells ,Polymerase Chain Reaction ,Cell Line ,Contig Mapping ,Cytosine ,Mice ,Chromosome 16 ,Chromosome regions ,Chromosome 19 ,Genetics ,Tumor Cells, Cultured ,Animals ,Humans ,In Situ Hybridization, Fluorescence ,Repetitive Sequences, Nucleic Acid ,Chromosome Aberrations ,Base Composition ,Chromosome Mapping ,General Medicine ,DNA ,Sequence Analysis, DNA ,Chromosomes, Bacterial ,Chromosome 17 (human) ,Blotting, Southern ,Chromosome 4 ,Chromosome 3 ,Genes ,CpG Islands ,Caco-2 Cells ,Chromosome 21 ,Chromosome 22 ,Sequence Alignment ,Pseudogenes ,HeLa Cells - Abstract
A physical map including four pseudogenes and 10 gene fragments and spanning 500 kb in the juxta-centromeric region of the long arm of human chromosome 21 is presented. cDNA fragments isolated from a selected cDNA library were characterized and mapped to the 831B6 YAC and to two BAC contigs that cover 250 kb of the region. An 85 kb genomic sequence located in the proximal region of the map was analyzed for putative exons. Four pseudogenes were found, including ΨIGSF3, ΨEIF3, ΨGCT-rel whose functional copies map to chromosome 1p13, chromosome 2 and chromosome 22q11, respectively. The TTLL1 pseudogene corresponds to a new gene whose functional copy maps to chromosome 22q13. Ten gene fragments represent novel sequences that have related sequences on different human chromosomes and show 97–100% nucleotide identity to chromosome 21. These may correspond to pseudogenes on chromosome 21 and to functional genes in other chromosomes. The 85 kb genomic sequence was analyzed also for GC content, CpG islands, and repetitive sequence distribution. A GC-poor L isochore spanning 40 kb from satellite 1 was observed in the most centromeric region, next to a GC-rich H1 isochore that is a candidate region for the presence of functional genes. The pericentric duplication of a 7.8 kb region that is derived from the 22q13 chromosome band is described. We showed that the juxta-centromeric region of human chromosome 21 is enriched for retrotransposed pseudogenes and gene fragments transferred by interchromosome duplications, but we do not rule out the possibility that the region harbors functional genes also.
- Published
- 1999