Chromosome 21


Human chromosome 21 is the smallest of the five acrocentric chromosomes and contains ∼1.4% of the genetic material in the genome. Although relatively gene‐poor, it contains around 10 genes Mb–1, a ribosomal ribonucleic acid (rRNA) gene cluster and three keratin‐associated protein clusters.

Keywords: chromosome 21; sequencing; Down syndrome; Alzheimer disease; leukaemia

Figure 1.

Unequal distribution of nonconserved genes on chromosome 21. Left axis indicates the number of genes in each 5 Mb interval; right axis indicates the proportion of conserved, minimally conserved and nonconserved genes among the total genes.



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Further Reading

Chromosome 21 gene function and pathway database with knowledge discovery tools: and

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GBF Department of Genome Analysis, Braunschweig: sequencing data.

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Yahya‐Graison, Emilie Ait, and Delabar, Jean Maurice(Jul 2007) Chromosome 21. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0005830.pub2]