High resolution array-CGH characterization of human stem cells using a stem cell focused microarray.

Human embryonic and induced pluripotent stem cells (ESCs, iPSCs) that are cultured for an extended period of time are susceptible to genomic instability. Chromosomal aberrations decrease the reliability and reproducibility of experiments and could deem the cells unusable for therapeutic purposes. The genetic stability of human ESCs and iPSCs is commonly monitored by karyotype analysis. However, this low-resolution technique can only identify large aneuploidies. A reliable, high-resolution technique to detect genomic aberrations at a cost comparable to karyotyping is needed to better characterize stem cell lines. We have designed a stem cell focused array-comparative genomic hybridization microarray that covers the entire genome at high resolution with increased probe coverage in over 60 stem cell associated genes and more than 195 cancer related genes. Several iPSC lines were analyzed using the focused microarray and compared with either karyotyping or a standard Agilent 44K microarray. In addition to the abnormalities detected by these platforms, the custom microarray identified several small duplications spanning stem cell and/or cancer related genes. Scientists using a stem cell focused microarray to characterize their stem cells will be aware of the structural variants present in their cells and be more confident in their experimental results.