 The study found that IPSC lines derived from the same donor were highly similar to one another, but genetic variation caused differences in the expression and methylation profiles of the cells, which could affect their functional capabilities. The researchers suggested that integration-free, bona fide IPSC lines from fibroblasts and blood could be combined in repositories to form biobanks. Since genetic variation can cause differences in the ability of IPSC lines to differentiate, it is important to include cells from many donors in biobanks.