Chromosome find could see disease breakthrough

Scientists have finished unravelling the largest human chromosome to be studied in detail so far, it was revealed yesterday.

Chromosome 7 has been linked to many human diseases including cystic fibrosis, hereditary deafness and cancer.

The new data, which is over 99% complete, shows the chromosome contains 153 million genetic code letters the DNA component chemicals whose sequences dictate what we are.

Among these are 1,150 genes, stretches of DNA that provide the instructions for making proteins.

Scientists also found 940 pseudo-genes pieces of DNA that look like genes but appear not to work. Unusually, large amounts of the chromosome sequence were duplicated, the team said in the journal Nature.

The repetitions may play a role in helping new genes to evolve, and may also be associated with disease.

Professor Richard Wilson, director of Washington University's Genome Sequencing Centre, said: "This work completes another volume in the genome encyclopaedia