Scientists sequence first human chromosome

(CNN) -- As the century draws to a close, scientists say a new book is being written that will change the way we see ourselves. It starts with the inaugural results of the Human Genome Project, which has sequenced the first human chromosome.

The second smallest, chromosome 22, was chosen to be sequenced first because it is one of the most densely packed, with 33.5 million pieces, or chemical components.

The achievement, made by a group of scientists from England, the United States, Canada, Sweden and Japan, is published in the journal Nature. It is an important step forward for the $3 billion Human Genome Project, which is working to detail the tens of thousands of genes in humans.

Researchers were able to find only 97 percent of the chromosome's genetic material, but the results are considered complete for now.

"For the first time we can see the entire landscape of a human chromosome, the basic unit of human inheritance, how the genes are organized, how they're laid out on the chromosome," said Dr. Francis Collins, chair of the National Human Genome Research Institute.

"I think this is probably the most important scientific effort that mankind has ever mounted," he said. "That includes splitting the atom and going to the moon."