In the human telomere, this sequence is repeated 250 to 1500 times, depending on cell type, with sperm chromosomes having the most repeats. Another type of repeated telomeric DNA, found adjacent to the terminal repeat, is species specific. Although it carries no genes, telomeric DNA is critical to chromosomal replication and stability. Scientists speculate that the ability of repetitive sequences to form novel structures may be responsible for maintaining each chromosome as a separate entity and preventing shortening during replication.
Telomere shortening is thought to play a role in the aging process and the onset of cancer.
Sequencing the entire genome has been the ultimate goal of the genome project from its inception, although this objective has sparked criticism from those who consider the sequencing of introns unproductive. Centromere Research Moyzis was also cited for his ongoing explorations in identifying the functional human centromere, a region of the chromosome that plays a key role during cell division. The discovery of human chromosome specific repetitive sequences located in or near the centromere led to immediate scientific and clinical applications, including diagnosis of some types of human genetic abnormalities and rapid identification of abnormal numbers of chromosomes in human cells. Moyzis, who was also recognized for his contributions to the successful initiation of the Human Genome Project, has served on numerous committees, including the DOE Human Genome Coordinating Committee and the NIH-DOE Joint Human Genome Program Advisory Committee. The LANL genome center is one of 19 U.S. centers whose goals are to map the estimated 100,000 genes residing along the human chromosomes and determine the sequence of the 3 billion bases contained in the human genome.