Researchers have deciphered the sequences of human chromosomes 13 and 19. The information, reported in two papers in the 01 April 2004 issue of Nature (Vol. 428, No. 6982, pp. 522-528 and pp. 529-535), should help to shed light on human diseases, such as cancer and diabetes.
Chromosome 19 has been sequenced by Jane Grimwood and colleagues. It has the highest gene density of all of the human chromosomes, more than double the genome-wide average. It also contains many features, such as dense repetitive stretches of DNA, which suggest that the chromosome has a rich biological and evolutionary significance. The chromosome contains various genes that have been implicated in heritable disorders, such as familial hypercholesterolaemia, myotonic dystrophy, and insulin-resistant diabetes.
In stark contrast, chromosome 13, sequenced by Andrew Dunham and colleagues, has one of lowest gene densities in the human genome, despite being a mid-size chromosome. It carries genes known to be involved in cancer, such as the breast cancer type 2 (BRCA2) and retinoblastoma (RB1) genes, and also contains DNA regions that have been linked with bipolar disorder and schizophrenia.
paper no: 
Wellcome Trust Sanger Institute
Tel: +44 1223 494918
paper no: 
Stanford Human Genome Center
Palo Alto, CA, USA
Tel: +1 650 320 5917
(C) Nature press release.
Message posted by: Trevor M. D'Souza