Chromosomes 9, 10 and 13 completed
3 June 2004
The analysis of the DNA sequence of human chromosome 13, produced by the Sanger Institute, was published in the 1 April 2004 issue of Nature. Within the 95.5 million letters of DNA code lie only 633 genes – fewer than on chromosome 22, which is less than half the size of 13. Among the genes on chromosome 13 are those that can predispose to breast cancer (BRCA2) as well as regions associated with schizophrenia.
For the first time, researchers have used methods to predict the locations of a class of genes – so-called microRNA genes – that are important in controlling the activity of other genes. MicroRNAs do not specify proteins, but bind to other RNA molecules. The importance of this type of control of gene activity has only been appreciated within the past two years. Today, several hundred genes for these RNAs are thought to be present in the human genome.
At the end of May, 13 was joined by the sequences of chromosomes 9 and 10, also produced by the Sanger Institute. The finished sequence of chromosome 9 is made up of nearly 110 million DNA base pairs, within which are almost 1200 genes. These include four genes that can cause sex reversal, all the human interferon type 1 genes (interferon is important in suppressing cancer development and in resisting virus infection), a gene implicated in neurodegenerative disease (CHAC), as well as a gene (ABL) that is involved in 90 per cent of chronic myeloid leukaemia (CML) cases. CML is one of the first cancers for which a treatment has been developed based on understanding the human genome sequence.
The 131 million base pairs of the chromosome 10 sequence includes 1357 genes, alterations in 85 of which are known to predispose to diseases such as a form of epilepsy (LGI1), obesity (GAD2) and cancer.
External links
- The DNA sequence and analysis of human chromosome 13 Dunham A et al. (2004), Nature 428: 522–28.
- DNA sequence and analysis of human chromosome 9 Humphray S J et al. (2004), Nature 429: 369–74.
- The DNA sequence and comparative analysis of human chromosome 10 Deloukas P et al. (2004), Nature 429: 375–81.