Manipulation of the human genome in human embryonic stem cells.

Human embryonic stem cells (HESCs) have a tremendous clinical and scientific importance since they may serve as a cell source for transplantation and as a system for the study of human development and disease. The genetic engineering of HESCs has become instrumental in achieving these goals. Here we discuss various methodologies to genetically manipulate HESCs and propose a variety of applications of the modified cells in basic and applied research.