Genomic Reprogramming Errors Do Not Accumulate with Serial Recloning in the Mouse. Mus musculus

To date, the success rate of serial animal cloning has decreased with increasing iterations and recloning has failed in all species after a few generations. This has suggested that recloning might be impossible because of the accumulation of lethal genetic or epigenetic abnormalities. Here, we carried out repeated recloning in the mouse using our somatic cell nuclear transfer method combined with a histone deacetylase inhibitor. The success rate of recloning did not decrease even after 25 iterations and more than 500 viable offspring have been obtained from a single original donor. Although the genomic reprogrammability of somatic cell nuclei did not improve, reprogramming errors or clone-specific abnormalities did not accumulate with recloning. Our results provide the first evidence that iterative recloning is possible, suggesting that animals might be able to be recloned indefinitely. Overall design: Brain and liver samples from 4 somatic cell clone (CC), 4 somatic cell clones of 20 generations (G20) and 4 normal controls (ICSI) neonate.