|Two More Human Chromosomes Are Complete| By Edward R. Winstead
Posted: March 31, 2004 Two more human chromosomes—one crowded
with genes, the other not—are now essentially complete, bringing
the total number of finished chromosomes to nine (out of 24). A
chromosome sequence is “finished” when most of the gaps and
errors in the DNA sequence from draft versions have been
eliminated. The newly sequenced chromosomes, 13 and 19, are
available online, and scientific papers about them appear this
week in Nature. Work on chromosome 19 began nearly two decades
ago and parallels the history of modern genomics. This
chromosome was among those originally targeted by the U.S.
Department of Energy for sequencing in the days before the human
genome project because it contained genes thought to be
associated with cancer and the repair of damaged DNA. Today,
nearly 100 genes on chromosome 19 have been linked to genetic
traits or diseases, including insulin-resistant diabetes. But no
genes have been found for at least 20 inher