Fluorescence imaging technology lets us see the inner workings of Blood cell birth.
Cells with clear endothelial morphology shown giving rise to blood cells. Left panel: phase contrast. Right panel: fluorescence detecting HIstone 2B-Venues expression.
1st pause in video: single mesodermal cell starting the colony
2nd pause: all cells in the colony exhibit a clear endothelial sheet mrophology
3rd pause: some cells lose tight integration into the endothelial sheet but keep adhering to endothelial cells
4th pause: Blood cells detach and are free-floating.
The arrow is following the starting cell and one daughter cell after each cell division until the end of the video