Editor's Summary

7 October 2010

Polyploidy in liver cells

Many liver cells are polyploid, containing 4, 8, 16 or more times the haploid chromosome complement, although the significance of the phenomenon is not known. A study in mice now shows that hepatocytes can both increase and decrease their ploidy in vivo. Ploidy reversal was previously thought to be exclusive to meiosis, but this work shows that it can also occur in normal somatic cells. Increases in ploidy occur through failed cytokinesis, and decreases as a result of multipolar mitosis. The resulting genetic heterogeneity might be advantageous following hepatic injury when 'genetically robust' cells could be selected from a pre-existing pool of diverse genotypes.

LetterThe ploidy conveyor of mature hepatocytes as a source of genetic variation

Andrew W. Duncan, Matthew H. Taylor, Raymond D. Hickey, Amy E. Hanlon Newell, Michelle L. Lenzi, Susan B. Olson, Milton J. Finegold & Markus Grompe