Human Genome Project: Chromosome X
The Wellcome Trust Sanger Institute played a substantial role in the sequencing and interpretation of the human genome, contributing almost one third of the gold-standard sequence, published in 2004. The Institute engaged in collaborative projects to sequence 9 of the 23 human chromosomes. This document is historical, presented here to provide a complete record. It might not have been updated and is a contemporary account.

Chromosome X publication front cover.
[Reprinted by permission from Macmillan Publishers Ltd: [Nature] (434 (7031): 257 - 420), ©2005]
The human X chromosome has a unique biology that was shaped by its evolution as the sex chromosome shared by males and females. Together with colleagues in the USA and Germany, we have determined 99.3% of the euchromatic sequence of the X chromosome. Our analysis illustrates the autosomal origin of the mammalian sex chromosomes, the stepwise process that led to the progressive loss of recombination between X and Y, and the extent of subsequent degradation of the Y chromosome. LINE1 repeat elements cover one-third of the X chromosome, with a distribution that is consistent with their proposed role as way stations in the process of X-chromosome inactivation. We found 1,098 genes in the sequence, of which 99 encode proteins expressed in testis and in various tumour types. A disproportionately high number of mendelian diseases are documented for the X chromosome. Of this number, 168 have been explained by mutations in 113 X-linked genes, which in many cases were characterised with the aid of the DNA sequence.
- Sequencing Centre: Wellcome Trust Sanger Institute, Baylor College of Medicine, Institut fur Molekulare Biotechnologie, Washington University, Max-Planck-Institute for Molecular Genetics
References
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The DNA sequence of the human X chromosome.
Nature 2005;434;7031;325-37
PUBMED: 15772651; PMC: 2665286; DOI: 10.1038/nature03440

