The groups of CAI Jun at CAS Beijing Institute of Genomics, GAO Shaorong at Tongji University and TIAN Jianhui at China Agricultural University showed by whole genome sequencing after sequential reprogramming that SNPs accumulated during the reprogramming steps. Functional annotation of SNPs demonstrated that these mutations would cause developmental failures in mice, but about two-thirds of the SNVs pre-existed in the all-iPSC mouse tissues which were generated during development, rather than merely by iPSC induction. In addition, retrotransposons were recurrently lost.

CAS news release, March 3, 2015