When DNA is damaged, cells can react through cell cycle checkpoints which allows repair to begin before further division can occur. There is also the prokaryotic SOS response which changes gene expression in bacteria as a result of DNA damage. This response is regulated by the production of certain proteins. Moreover, eukaryotic cells also react to DNA damage through producing proteins that begin the process of DNA repair. 8. Mice are often the favored mammalian in the testing of aging interventions. This is often because of the fact that there are many mice easily available for testing but also the fact that "generation time is short" (Yuan et al. 2011). Essentially, the aging process and testing in interventions can be done on a much shorter time scale then with tests using monkeys.

9. Enzymes may change the transcription patterns of a cell by adding chemical groups to histone proteins. This process increases the sensitivity to DNase I digestion.

10. Old stem and progenitor cells in a young systemic environment can be rejuvenated. Heterochronic parabiosis can be restored through the activation of Notch signaling and a "regenerative capacity of aged satellite cells" (Conboy et al. 2005).

References

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