[Albert de Roos is a cell biologist from Amsterdam, who has previously graced Telic Thoughts with this guest post about applying engineering principles to evolution. We've invited him to write about his latest article, published in the journal Artificial Life. Not because we agree with everything he has to say (nor vice versa), but because we find it to be an interesting approach, which may jolt researchers into thinking about evolution in new terms. Don't forget to check out Albert de Roos' blog]

A design hypothesis for the evolution of the nucleus
By Albert de Roos, Ph.D. Cell Biology

Recently, I published an article about the origin of the nucleus. Basically, I pose that the nucleus arose in evolution when a nucleus-like cell generated an extra plasma membrane around itself. Or in other words, when we take the current nucleus, we are looking at the direct descendent of a free living ancestor cell. Genetic material that is wrapped in a double membrane with large simple pores in them that keeps macromolecules such as DNA, RNA and proteins inside, while nutrients and waste is free to diffuse in and out.

This article is not 'just another theory' about the origin of the nucleus, but it is derived from an engineering framework named 'design by contract'. This concept is used in the development of software where components of systems communicate according to defined interfaces or contracts. As long as you don't change existing interfaces, you can extend the system. You can directly apply that to evolution: you can add new functionality, as long as you keep existing interfaces intact. The conserved mechanisms for translation, transcription, splicing etc. can be considered to reflect these constant interfaces in this engineering view. Conservation is thus regarded as an inevitable consequence of extension since any evolutionary process that would require extensive rework in critical systems would never survive because of the direct fitness costs.

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