[radicalcut]

Human cells may have tens of times more forms of proteins expressed from these 23,000 genes if you take into account alternative splicing of pre-mRNA and many other post-translational modifications. These are all processes which prokaryotic organisms like M. genitalium generally lack.

Even when we look aside from the level of DNA/RNA there are huge differences in morphological organisation of eukaryotic cells when compared to most prokaryotes: dynamic compartmentalisation of cytoplasm, different types of cytoskeleton, vesicle trafficking, complex signal transduction networks instead of usually simple two-component regulatory systems... So the simulation of whichever human cell type could be much more complicated than one could initially thought.

I don't want to sound too much pessimistic, as someone with background in both CS and molecular biology I'm truly excited about this, but I still had to cool myself down a little bit after reading the article. I can't wait to read the original paper.