UH Manoa Cloning Team in March Issue of Nature Medicine

University of Hawaiʻi
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Posted: Feb 28, 2002

A team of researchers from the University of Hawaiʻi at Mānoa‘s Institute for Biogenesis Research (IBR) are featured on the cover of the March issue of Nature Medicine.

In an article titled "Cloned mice have an obese phenotype not transmitted to their offspring," researchers Kellie L.K. Tamashiro, formerly of UH Mānoa and now with the University of Cincinnati; Teruhiko Wakayama formerly of UH Mānoa and now with Advanced Cell Technology in Massachusetts; Hidenori Akutsu formerly of UH Mānoa and now with Fukushima Medical University in Japan; and Yukiko Yamazaki and Ryuzo Yanagimachi, both of UH Mānoa, the adverse effects of mammalian reproductive cloning on the health of offspring remain a key concern in the application of this technology.

In their cloning of mice, they discovered that adult-onset obesity can be yet another consequence of cloning. Their research suggests that the obesity phenotype may be a function of epigenetic medications of donor DNA that are ultimately not inherited.

Using the technique of somatic cell transfer to produce cloned mice-that is placing the nucleus of an adult cell into an enucleated donor cell, the researchers measured various parameters of obesity and found the cloned mice were heavier than controls after 10 weeks growth. The clones were not simply larger than controls, but displayed all the characteristics of obesity-increased body fat, increased leptin levels, and raised plasma levels of insulin. Importantly, the offspring of these mice were not obese, meaning that the abnormality was not passed on through the germline.

The discovery of this obese phenotype in cloned mice has implications for the advancement of the cloning technique. Research indicates that an epigenetic modification, rather than a genetic change, may be responsible for the low success rate of cloning and for producing aberrant phenotypes in surviving cloned animals. As the success rate of cloning techniques using adult somatic cells is less than 3%, reproduction by natural mating may be recommended as soon as cloning produces offspring with specific desired traits.