Viviane Callier writes:

Each of us starts life as a single cell. To develop into a complex, multicellular being, that cell must divide, and then those cells must divide again, and again — and then these stem cells start to specialize into different types, with different destinies in our bodies. In the first week, our cells reach their first turning point: They must become either placenta or embryo. Then, in the developing embryo, cells form three primary layers — ectoderm, mesoderm and endoderm — which, over time, become skin, neurons, heart, gut, and so on.

These determinations of cells’ fates — what type of specialized cell they will become — occur in stages throughout embryonic development. Because each cell type has a characteristic pattern of gene activity, scientists assumed that the decisions cells make are dictated by genes: specifically, networks of genes that turn each other on and off, initiating a cascade that forms the correct types of cells in the correct order.

But genes are not the whole story. New research has shown the extent to which cell metabolism — the chemical reactions within a cell that provide energy and materials for growth — has an important, underappreciated role in directing cell fates.

“Metabolism is more than just housekeeping in stem cells, especially embryonic stem cells,” said Jan Żylicz, a developmental biologist at the University of Copenhagen. “It’s a crucial pathway that regulates decision-making processes.” [Continue reading…]