Human rRNA gene clusters are recombinational hotspots in cancer.

@article{Stults2009HumanRG,
  title={Human rRNA gene clusters are recombinational hotspots in cancer.},
  author={Dawn Michelle Stults and Michael W Killen and E. P. M. Williamson and Jon S. Hourigan and Hern{\'a}n Vargas and Susanne M. Arnold and Jeffrey A Moscow and Andrew J. Pierce},
  journal={Cancer research},
  year={2009},
  volume={69 23},
  pages={
          9096-104
        }
}
The gene that produces the precursor RNA transcript to the three largest structural rRNA molecules (rDNA) is present in multiple copies and organized into gene clusters. The 10 human rDNA clusters represent <0.5% of the diploid human genome but are critically important for cellular viability. Individual genes within rDNA clusters possess very high levels of sequence identity with respect to each other and are present in high local concentration, making them ideal substrates for genomic… 

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