Epigenetic regulation of genetic integrity is reprogrammed during cloning

Patricia Murphey, Yukiko Yamazaki, C. Alex McMahan, Christi A. Walter, Ryuzo Yanagimachi, John R. McCarrey

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Cloning by somatic cell nuclear transfer (SCNT) circumvents processes that normally function during gametogenesis to prepare the gamete genomes to support development of new progeny following fertilization. One such process is enhanced maintenance of genetic integrity in germ cells, such that germ cells typically carry fewer spontaneously acquired mutations than somatic cells in the same individual. Thus, embryos produced from somatic cells by SCNT could directly inherit more mutations than naturally conceived embryos. Alternatively, they could inherit epigenetic programming that predisposes more rapid accumulation of de novo mutations during development. We used a transgenic mouse system to test these possibilities by producing cloned midgestation mouse fetuses from three different donor somatic cell types carrying significantly different initial frequencies of spontaneous mutations. We found that on an individual locus basis, mutations acquired spontaneously in a population of donor somatic cells are not likely to be propagated to cloned embryos by SCNT. In addition, we found that the rate of accumulation of spontaneous mutations was similar in fetuses produced by either natural conception or cloning, indicating that cloned fetuses do not acquire mutations more rapidly than naturally conceived fetuses. These results represent the first direct demonstration that the process of cloning by SCNT does not lead to an increase in the frequency of point mutations. These results also demonstrate that epigenetic mechanisms normally contribute to the regulation of genetic integrity in a tissue-specific manner, and that these mechanisms are subject to reprogramming during cloning.

Original languageEnglish (US)
Pages (from-to)4731-4735
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number12
StatePublished - Mar 24 2009


  • Epigenetic
  • Mutagenesis
  • Reprogramming

ASJC Scopus subject areas

  • General


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