Editor's Summary

13 September 2007

The not-so-immortal strand

In 1975, John Cairns proposed the 'immortal strand' hypothesis as a mechanism by which adult stem cells might minimize accumulation of mutations. This is achieved by selectively retaining chromosomes containing 'old' DNA as shown by the analysis of the DNA strands that incorporate radioactive label or a nucleotide analogue such as bromodeoxyuridine (BrdU). A new contribution to this ongoing debate is published in this issue. Kiel et al. show that the immortal strand model is not a general property of stem cells since it does not apply to haematopoietic stem cells. These cells cannot be identified on the basis of BrdU label retention, and do not retain older DNA during division.

Letter: Haematopoietic stem cells do not asymmetrically segregate chromosomes or retain BrdU

Mark J. Kiel, Shenghui He, Rina Ashkenazi, Sara N. Gentry, Monica Teta, Jake A. Kushner, Trachette L. Jackson & Sean J. Morrison

doi:10.1038/nature06115

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