The cover image is in the style of a painting by the 19th century artist Paul Klee “Fire in the evening” (1929). Somatic cells need for genes to be reprogrammed to iPCS. However, only certain stoichiometric combinations of gene expression (symbolized by the color and size of the bars that represent one of the four different genes) render high yield of pluripotent stem cells. See the accompanying article by Tiemann et al. in this issue.
Cover design by Bärbel Beran [www.beran-design.de].