Assessing the complexity of embryonic somites with single cell genomics

A fascinating question in biology asks how multicellular organisms arise from a single cell: the fertilized egg. During embryogenesis, naïve and still plastic progenitor cells communicate with each other, first to form different layers and to organize the main body axes, and later to build specialized organs with highly differentiated cell types and functions. The cells in an embryo coordinate these complex events by activating gene expression programmes, often in response to extrinsic signals. The control of cell differentiation is important throughout the life of an organism, for example to repair tissue after injury or for growth and remodeling using tissue resident stem cells, which activate cellular differentiation programmes similar to those used in the embryo. However, many details of how cells progressively differentiate - at the right time and in the right place - are still poorly understood. This will be addressed here in developing somites, paired segments along the axis of vertebrate embryos, which generate much of the musculoskeletal system from an initially homogenous population of cells. The project will use advanced (low input) sequencing techniques to determine molecular profiles of progenitor cells present in early somites. By looking at different stages of somite differentiation we will characterize cellular intermediates and transition states as more specialised cell types arise.