21.   In one new experiment, researchers injected single cells into early stage mouse embryos and checked the resulting animals after birth.

22.   The new work, done in mouse embryos, suggests that a particular gene crucial for early development is usually not reprogrammed properly.

23.   The researchers then injected embryonic stem cells, extracted from an early mouse embryo and capable of growing into any type of cell.

24.   The Sloan-Kettering researchers stumbled on the role of genes in angiogenesis while they were investigating their place in the brain development of mouse embryos.