Recent genetic analyses in yeasts and biochemical studies in vertebrat
e cells have led to the discovery of a family of putative ATPases that
play a fundamental role in chromosome condensation and segregation in
mitosis. One of the members was also found to be involved in dosage c
ompensation in Caenorhabditis elegans, providing a new link between gl
obal regulation of gene expression and chromosome structure. This uniq
ue family of proteins may control higher-order chromosome dynamics by
regulated self-assembly or mechanochemical activity.