Resolving the Duplications Within the Human Genome

Summary

The August 9 issue of Science magazine highlights a report from an Office of Science funded research team led by Dr. Evan E. Eichler at the Case Western Reserve University (CWRU). The human genome is dotted with duplicated chromosome segments that often differ only in their base sequences by a few percent or less. These duplications are troublesome barriers to DNA sequencing and mapping. Dr. Eichler’s research, with support from both the Office of Science and the National Institutes of Health, describes the complex pattern of duplications found in the human genome. These duplications are very important in evolution. While one copy of a gene can maintain and transmit essential functions between generations, a duplicated gene is freer to evolve novel, and perhaps beneficial, capabilities. However, duplications are also particularly prone to the development of deleterious deletions and chromosomal rearrangements. Indeed, some of the duplicated sites identified by Dr. Eichler’s research correlate with genetic diseases. Fully deciphering the implications of the numerous duplications found in the human genome is an interesting and important task that will continue long after the completion of the human genome sequence itself.