Within the field of
developmental biology one goal is to understand how a particular cell (or embryo) develops into the final cell type (or organism), essentially how a cell’s fate is determined. Within an embryo, 4 processes play out at the cellular and tissue level to essentially create the final organism. These processes are
cell proliferation, cell specialization, cell interaction and cell movement. Each cell in the embryo receives and gives cues to its neighboring cells and retains a cell memory of its own cell proliferation history. Almost all animals undergo a similar sequence of events during
embryogenesis and have, at least at this developmental stage, the three
germ layers and undergo
gastrulation. While embryogenesis has been studied for more than a century, it was only recently (the past 15 years or so) that scientists discovered that a basic set of the same
proteins and
mRNAs are involved in all of
embryogenesis. This is one of the reasons that model systems such as the fly (
Drosophila melanogaster), the mouse (
Muridae), and the leech (
Helobdella), can all be used to study embryogenesis and developmental biology relevant to other animals, including humans. What continues to be discovered and investigated is how the basic set of proteins (and mRNAs) are expressed differentially between cells types, temporally and spatially; and whether this is responsible for the vast diversity of organisms produced. This leads to one of the key questions of developmental biology of how is cell fate determined.