Somatic cells harbor random heteroplasmic mitochondrial DNA mutations, which are considered to contribute to aging. In this issue of The EMBO Journal, Perales‐Clemente et al (2016) show that mtDNA mutations, present at low levels in the starting fibroblasts, become enriched in iPS cells and lead to functional defects in iPS‐derived cells. In another recent study, Kang et al (2016) demonstrated that accumulation of mtDNA mutations of somatic origin in iPSCs is age related.
See also: E Perales‐Clemente et al (September 2016) and
E Kang et al (May 2016)
Genetic integrity of induced pluripotent stem (iPS) cells is important for both therapeutic and research applications. Several studies have shown that different nuclear DNA aberrations, point mutations, copy number variation, and chromosomal rearrangements are frequent in iPS cells and that the majority of these arise during the reprogramming process (Oliveira et al, 2014). Mitochondrial DNA mutations have also been shown to be present in iPS cells (Prigione et al, 2011), but their extent and origin, as well as their effects on reprogramming to pluripotency, remain unknown. The mitochondrial genome is small but very gene‐rich. It encodes genes essential for oxidative phosphorylation and cellular energy production. Mutations in the mitochondrial DNA (mtDNA) cause a variety of human inherited diseases and are implicated in many age‐related …