title: The (not so) immortal strand hypothesis.
abstract: BACKGROUND
  Non-random segregation of DNA strands during stem cell replication has been proposed as a mechanism to minimize accumulated genetic errors in stem cells of rapidly dividing tissues. According to this hypothesis, an "immortal" DNA strand is passed to the stem cell daughter and not the more differentiated cell, keeping the stem cell lineage replication error-free. After it was introduced, experimental evidence both in favor and against the hypothesis has been presented.
  
  
  RESULTS
  Using a novel methodology that utilizes cancer sequencing data we are able to estimate the rate of accumulation of mutations in healthy stem cells of the colon, blood and head and neck tissues. We find that in these tissues mutations in stem cells accumulate at rates strikingly similar to those expected without the protection from the immortal strand mechanism.
  
  
  CONCLUSIONS
  Utilizing an approach that is fundamentally different from previous efforts to confirm or refute the immortal strand hypothesis, we provide evidence against non-random segregation of DNA during stem cell replication. Our results strongly suggest that parental DNA is passed randomly to stem cell daughters and provides new insight into the mechanism of DNA replication in stem cells.
authors.affiliation: Division of Biostatistics and Bioinformatics, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA. Electronic address: ctomasetti@jhu.edu.
authors.forename: Cristian
authors.initials: C
authors.lastname: Tomasetti
authors.affiliation: Program for Evolutionary Dynamics and Department of Mathematics, Harvard University, Cambridge, MA, USA.
authors.forename: Ivana
authors.initials: I
authors.lastname: Bozic
mesh_terms: D002454:Cell Differentiation / Q000235:genetics*; D002455:Cell Division / Q000235:genetics; D004247:DNA / Q000235:genetics*; D004261:DNA Replication / Q000235:genetics*; D006801:Humans; D000067552:Mutation Accumulation; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*
chemical_list: D004247:DNA