The energetics of genome complexity

"Virtually every ‘eukaryotic’ trait is also found in prokaryotes, including nucleus-like structures, recombination, linear chromosomes, internal membranes, multiple replicons, giant size, extreme polyploidy, dynamic cytoskeleton, predation, parasitism, introns and exons, intercellular signalling (quorum sensing), endocytosis-like processes and even endosymbionts. Bacteria made a start up virtually every avenue of eukaryotic complexity, but then stopped short. Why?"

The authors suggest that it has everything to do with the energetics of expressing genes and that eukaryotic cells can only express their genes because of their symbioses with mitochondria. Because mitochondrial symbiosis evolved only once, so did eukaryotic cells.

Admittedly, this has very little to do with molecular anthropology, but it's still a fascinating read.