Scientists report progress in completing sequencing of human genome

Monday, April 14th 2003, 12:00 am
By: News On 6

WASHINGTON (AP) _ Scientists who three years ago said they had virtually completed a map of the human genetic code now report progress in understanding the last few pieces of one of the world's most complex puzzles.

The sequencing of the human genome puts humankind on the verge of a new era of breakthroughs in treating disease, say researchers involved in the project.

Dr. Francis Collins, director of the federal National Human Genome Research Project, planned to announce the update Monday, with Dr. Elias Zerhouni, director of the National Institutes of Health, and James Watson, who shared the Nobel Price for discovering the building blocks of life that have now been decoded.

The genome is the collection of genes that form the DNA that contains the instructions for life. In humans it's about 3.12 billion pairs of chemicals that form between 35,000 and 40,000 genes.

A gene is a group of those pairs, and each gene is a single instruction for the makeup of a being. Faulty genes can lead to various diseases; researchers hope that once they can read the entire code they can figure out where problems exist and, one day, correct them.

``We have caught a glimpse of an instruction book previously known only to God,'' Collins said when the nearly complete work was announced.

``The promise of this research is great for alleviating human suffering. If research continues to proceed vigorously, we can expect medicine to be transformed dramatically in the coming decades,'' he later told a Senate subcommittee.

In the earlier announcement, Collins said about 97 percent of the chemical pairs had been identified. He said researchers eventually hoped to sequence the genome to an accuracy of 99.9 percent. Because every human being has a unique genetic pattern, researchers are not expected to ever reach 100 percent.

It was just 50 years ago that Watson and collaborator Francis Crick, working at Cambridge University in England, were able to figure out the structure of DNA.

The DNA molecule resembles a twisted ladder. It is made up of just four chemicals, called bases, with each ``rung'' made from a pair of these bases. The bases provide the genetic code. Just as a four-letter alphabet could spell out words, the sequence of the four kinds of bases along the length of the DNA molecule spells out the information stored in genes.