Human genome rife with 400 ‘fragile zones’

Researchers have uncovered evidence that major evolutionary changes are more likely to occur in approximately 400 ‘fragile’ genomic regions that account for only 5 percent of the human genome. The findings, reported in the June 24 issue of the Proceedings of the National Academy of Sciences (PNAS), undercut the widely held view among scientists that evolutionary breakpoints ? disruptions in the order of genes on chromosomes ? are purely random. Apart from its implications for evolutionary theory, the study could have major implications for medical research related to diseases such as leukemia, which are caused by clinical (rather than evolutionary) chromosomal breakpoints.