The key structures of embryonic development

Some epigenetic processes (for example protein synthesis and ribosome self-assembly) also take place in prokaryotes, and yet these cells do not give rise to embryos. It is not epigenesis as such, therefore, that accounts for development, but a particular type of epigenesis that prokaryotes do not have. It could be pointed out that prokaryotes lack the complex structures of the eukaryotic cell, but this does not explain their lack of embryonic potential. Protozoa, for example, do have the eukaryotic cell structure but they too are incapable of producing embryos. 

It is not epigenesis as such, nor eukaryotic cell structure, that accounts for embryonic development, and we are bound to conclude that development is based on something which does not exist in 

As always happens, a new conclusion inevitably raises new questions, and in this case the first problem that calls for our attention is the origin of cell memory, a problem which takes us back to evolution and to the evolutionary mechanisms. Now, however, we have something new to discover in the past, and we can look at the history of life from a point of view which has not been considered before. 

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