Live imaging of avian embryos

Our understanding of vertebrate development relies on the ability to visualize cell and tissue behaviors. However, imaging a live embryo poses the dual challenges of achieving single-cell resolution and sustaining embryo health. Here, we present the advantages and limitations of live imaging of avian embryos. We highlight innovative modifications to whole-embryo or tissue slice cultures combined with two-photo, confocal, or wide-field microscopy that allow for a greater flexibility to study complex three-dimensional events, such as avian gastrulation and neural crest migration. We discuss advances in cell labeling that include ovo photoactivation of green fluorescent protein and focal electroporation that permit single-cell tracing with higher fidelity and reproducibility. We include exciting advances in avian transgenics research that promise to streamline the process of cell labeling and allow dynamic imaging shortly after egg opening. These advances in live avian embryo imaging, combined with tissue transplantation and accessibility, make avian embryos a powerful model system for studying cellular and molecular mechanisms of morphogenesis, migration, and cell-fate specification