Describe:-(i) how induced pluripotent stem cells (iPSCs) are isolated(ii) how iPSCs can be used to study human development(iii) how iPSCs can be used to model human disease and to develop therapies for degenerative diseasesi) iPSCs are adult stem cells that have been genetically reprogrammed to behave like pluripotent stem cells found in embryos, i.e. capable of differentiating into any cell type in the body human. This was first successfully completed in mice in 2006 by Shinya Yamanaka and his team (Takahashi et al., 2006), then in humans in 2007 by both Yamanaka (Takahashi et al., 2007), and James Thomson and his team in America. independently (Yu, et al., 2007). Yamanaka and Thomson's methods were similar. In the report by Yu et al. it is stated that “since development is dictated by epigenetic rather than genetic events, differentiation is, in principle, reversible” (Yu et al., 2007 p. 1917). In Yamanaka and team's method, viral transduction using retroviruses containing four human transgenes (Oct3/4, Sox2, Klf4, and c-Myc) as transduction factors was used to reverse the differentiation and gene expression of human dermal fibroblasts . The resulting cells were morphologically similar to embryonic stem cells. (Takahashi et al., 2007 p. 862-863) Thomson and team used a very similar method, however they used Oct4, Sox2, Nanog and Lin28 in a lentiviral system (Yu, J, et al., 2007 p. 1917). One of the major limitations of iPSCs currently is the presence of viral vectors used to transduce the reprogramming factors. These have been shown to cause the development of tumors in mice due to the reactivation of c-Myc, an oncogene (a gene with the potential to transform a cell into a cancer cell under certain circumstances). iSPCs were g...... half of paper ......em-cells-101/why-are-pluripotent-stem-cells-important/. [Accessed 27 April 14].National Institutes of Health. 2009. Stem Cell Basics: What Are Induced Pluripotent Stem Cells. [ONLINE] Available at: http://stemcells.nih.gov/info/basics/pages/basics10.aspx. [Accessed 27 Apr 14]Park, I, Arora, N, Huo, H, Maherali, N, Ahfeldt, T, Shimamura, A, Lensch, M, Cowan, C, Hochedlinger, K, & Daley, G, 2008 Disease - Specific induced pluripotent stem cells. Cell, 134, 877-886.Soldner, F, Hockemeyer, D, Beard, C, Gao, Q, Bell, G, Cook, E, Hargus, G, Blak, A, Cooper, O, Mitalipova, M, Isacson, O, & Jaenisch, R, 2009. Patient-derived induced pluripotent stem cells in Parkinson's disease lacking viral reprogramming factors. Cell, 136, 964-977.Saha, K, & Jaenisch, R, 2009. Technical challenges in using human induced pluripotent stem cells to model disease. Cellular stem cell, 5, 584-595.