Human cells generally contain 23 pairs of chromosomes, with each pair containing a chromosome from each parent. These structures carry the genes, a segment of DNA with a particular purpose that contain instructions for the body's development and function. An international group of researchers have released the full sequence of chromosome 14, the longest chromosome ever sequenced. The newest human sequencing endeavour holds promise in the fights against numerous diseases linked to crucial immune system function as well as genes associated with more than 60 diseases. These diseases include early onset Alzheimer's disease and other neurodegenerative problems. Researchers from Genoscope-Centre National de Sequencage, France discovered that chromosome 14 contains 1,050 genes and gene fragments. The chromosome also appears to contain 393 non-active "pseudogenes." Other diseases with genes present on this chromosome are spastic paraplegia, neurodegenerative conditions marked by progressive weakness and stiffness in the legs, and Usher syndrome, which results in early hearing loss and gradual loss of vision. Sequencing the abnormal forms of the genes that cause disease may one day lead to new treatments for those conditions. It is suggested that researchers could possibly mould new therapies around the proteins manufactured by abnormal genes. And although gene therapy techniques have had limited success, future endeavours may one day succeed in replacing an abnormal copy of a gene with a healthy copy.

Nature January 2003, doi:10.1038/nature01348