In vitro differentiation of ES cells occurs when the cells are allowed to aggregate in suspension culture in the absence of mouse embryonic fibroblast (MEF) feeders and leukemia inhibitory factor (LIF). Hanging drops provide a uniform aggregate size, which is then expanded by continued growth in suspension culture. The embryoid bodies are then plated and allowed to differentiate further in culture. - [Read Differentiation of Embryonic Stem (ES) Cells Using the Hanging Drop Method]
Karyotyping is a valuable research tool used to determine the chromosome complement within cultured cells. It is important to keep in mind that karyotypes evolve with continued culture. Because of this evolution, it is important for the interpretation of biochemical or other data, that the karyotype of a specific sub-line be determined. - [Read Karyotyping Protocol]