Being transparent and amenable to laboratory manipulation, C. elegans cell lineage was first completed by John Sulston in the 1980s. Cell lineage is similar to the family tree of cells. The development of a cell's predecessor and successors can be determined from the lineage.
A bit of history:
"...[B]ut it sufficed to get us started in earnest on the cell lineage. The significance was that although Sydney had wanted from the beginning of the project to follow cell lineages, it was presumed that the most interesting development happened in the egg. So this was the only stage that had been studied, but it was proving very difficult to see anything. It meant, however, that there were already Nomarski DIC (differential interference contrast) microscopes in the lab.
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The transparency of C. elegans made the lineaging possible. Dr. John Sulston spent one and a half years (in the dark) to complete the C. elegans cell lineage. Dr. Sulston hand-drew the real-time worm development. Originally, the C. elegans embryo development wasn't recorded in video for lineaging.
"The cell lineage is the description of the history of each embryonic cell, beginning with the un-cleaved egg. The products of every division are traced until the rudiments of the embryonic organs become distinct." (Ways of Knowing, John Moore, p. 494)
As the complete cell lineage (JPG, 1 MB) shows, from top to bottom, you can see an un-cleaved, just fertilized zygote, P0 cell divides into two daughter cells (AB and P1 cells) . The two daughter cells then divide into more daughter cells that eventually form a map and enable one to trace a cell's predecessors and successors.
Later, Nomarski optics (also known as Differential Interference Contrast (DIC) microscopy) was also used:
This video shows the embryonic development from 1-cell to 100-cell:
(QuickTime, 18 MB)
The C. elegans Cell Lineage Module: instructional materials for teaching cell lineage by inquiry. Resources can be used/adapted for teaching disciplines (e.g.: developmental biology, cell biology, genetics) with other instructional approaches (e.g.: lectures, lab) as well. Animations, movies, images and hands-on tools are included.