Stem cell growth, required for kernel development, is controlled in corn by a set of genes called CLEs. But how these genes change the corn is complicated. Using CRISPR genome editing, CSHL researchers found they could change kernel yield and ear size by fine-tuning the activity of one of the CLE genes, ZmCLE7. In the image: an unmodified corn cob with normal ZmCLE7 gene activity (1) is packed with regular rows of kernels. Shutting off ZmCLE7 (2) shortened the cob, disrupted row patterns, and lowered kernel yield. However, decreasing the same gene's activity (3) led to an increase in kernel yield, while increasing the gene's activity (4) decreased the kernel yield.