"The DNA Sequence of Human Chromosome 21".

Consortium Institutions:
¹ RIKEN, Genomic Sciences Center, Sagamihara 228-8555, Japan
² Institut fur Molekulare Biotechnologie, Genomanalyse, D-07745, Jena, Germany
³ Department of Molecular Biology, Keio University School of Medicine, Tokyo 160-8582, Japan
⁴ GBF (German Research Centre for Biotechnology), Genome Analysis, D-38124 Braunschweig, Germany
⁵ Max-Planck-Institut fur Molekulare Genetik, D-14195 Berlin-Dahlem, Germany
Collaborating Institutions:
⁶ RIKEN, Life Science Tsukuba Research Center, Tsukuba 305-0074, Japan
⁷ Cancer Genomics Division, National Cancer Center Research Institute, Tokyo 104-0045, Japan
⁸ Human Genome Center, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
⁹ UMR 8602 CNRS, UFR Necker Enfants-Malades, Paris 75730, France
¹⁰ Eleanor Roosevelt Institute, Denver, Colorado 80206, USA
¹¹ Medical Genetics Division, University of Geneva Medical School, Geneva 1211, Switzerland
¹² CNRS UPR 1142, Institut de Biologie, Montpellier, 34060, France
¹³ School of Pharmacy, University of London, London WC1N 1AX, UK

Abstract:

Chromosome 21 is the smallest human autosome. An extra copy of chromosome 21 causes Down syndrome, the most frequent genetic cause of significant mental retardation, which affects up to 1 in 700 live births. Several anonymous loci for monogenic disorders and predispositions for common complex disorders have also been mapped to this chromosome, and loss of heterozygosity has been observed in regions associated with solid tumours. Here we report the sequence and gene catalogue of the long arm of chromosome 21. We have sequenced 33,546,361 base pairs (bp) of DNA with very high accuracy, the largest contig being 25,491,867. Only three small clone gaps and seven sequencing gaps remain, comprising about 100 kilobases. Thus, we achieved 99.7% coverage of 21q. We also sequenced 281,116 bp from the short arm. The structural features identified include duplications that are probably involved in chromosomal abnormalities and repeat structures in the telomeric and pericentromeric regions. Analysis of the chromosome revealed 127 known genes, 98 predicted genes and 59 pseudogenes.

Additional References:

1. "The DNA Sequence of Human Chromosome 22".

2. "A BAC-Based Physical Map of the Major Autosomes of Drosophila melanogaster".

3. "The Fourth Chromosome of Drosophila melanogaster: Interspersed Euchromatic and Heterochromatic Domains",

4. "Ultrastructural Continuity Between Active and Repressed Chromatin".

5. "Mechanisms of Repression and De-Repression within Interphase Chromatin".

6. "Oncogenes as Molecular Targets within Active Chromatin".