The
Caenorhabditis elegans embryo is particularly amenable to
microscopy and embryological studies because of its short developmental
time, transparent shell, and nonpigmented
cells. The agar
mount described in this protocol is an easy way to prepare live
C. elegans embryos for
microscopic visualization. The
mount slightly
embeds the embryo in agar to hold it in place. The
mount also
slightly compresses the embryo to provide consistent orientation
such that every embryo will be positioned with either its right
side or its left side facing the
objective. Other techniques
can result in random orientations that complicate
analysis and
make identification of individual blastomeres more challenging.