Here is a time lapse video some friends of mine (Daniel Castranova & Brant Weinstein) made of the always photogenic zebrafish embryo development.
The video goes up to a 22 hours old embryo.
The egg inside the shell is about 800 um across (0.8 mm).
It uses differential interference contrast optics.
The green is marks the developing vascular system. The embryo is engineered to make GFP (Green Fluoescence Protein) in developing blood vessel cells.
The first synchronously dividing cells are going through cleavage.
After they stop dividing synchrously, the pile of cells spread over the yolk and undergo gastrulation (forming the three primary tissue layer (endoderm, mesoder, and ectoderm)) and start to form the body of the embryo.
The head forms on the left and the tailbud on the right.
The blocks of tissue that form toward the top are the developing somites (mesodermal segments) which form structures like for vertebrae and ribs, and the muscles that attach to them.
It gets twitchy near the end due to spontaneous neural activity.
This kind of thing has been a pretty standard in labs for >20 years.
It shows several of the many reasons zebrafish are popular as model research organisms:
- Fast development (they have a function neural reflex by 18 hours).
- Optically clear for 18-24 hours.
- Great embryology for studying.
- Zebrafish (thanks to Crisper) also now have many useful forward and backward genetic tricks.
- Can get 100-200 fertilized eggs from a female/ week (good for genetics).
- Generation time (egg to egg) of 2-4 months.
- Simple husbandry and breeding requirements (can be done in a warehouse-like system).
