An animation created from stills captured from a video film.
Video from Sjörgren, Lundin, Hamberger, Löfman, & Nillson - Department of OBS & GYN, Göteborg University, Sweden.

This is a loop sequence - you watch the animation over and over again until you either instruct the browser to stop, or press ESC, or return to the Home Page.

• The sequence starts at the pronucleate stage which becomes visible at about 18-22 hours after successful insemination,
• Cleavage to the 2 cell (blastomere) stage takes place fairly rapidly,
• The two cells then begin divide
• One cell divides quite quickly but the second takes longer.
• Finally the four cell stage is reached.