IBC University Stuttgart

Systems biology

"Now, my own suspicion is that the universe is not only queerer than we suppose, but queerer than we can suppose". – J.B.S. Haldane
(see also Richard Dawkins on ted.com)

Life science has entered a new field, which might be as challenging as the big issues of physics: particle research and cosmology. The need is to comprehend the stunning complexity, adaptility and robustness of living systems. These are the fundamental and challenging aims of systems biology.

The classical concept of molecular cell biology is dissection of biological systems into discrete pieces, which then - following "hypothesis driven" approaches are inspected for their components and functional interplay. This strategy celebrated great success in explaining numerous biological processes (in terms of physics and chemistry). Moreover, the belief was that putting together the constituent parts - in a so called "bottom-up" process - would yield an all-encombassing modell of the cell.

In the last decade life science has made great progress in the development of automatized high-through technologies, which allow the inspection of cells as a whole; this appraoch is called the "top-down" strategy. Beginning with sequencing of genomes (genomics), now entire sets of metabolites (metabolomics) as well as transcripts and proteins (proteomics) - partially also including their dynamics - have been analyzed. Moreover, great improvements have been made in the automotized cell wide inspection of physical and genetic protein-protein interactions. Especially, the latter approaches have fortified describing biological systems as networks. Based on this work, many biolgists have realized that the classical concept has its limitation and that assembling the whole from parts may not only be aa overhelming multi-dimensional problem, but yield an incomplete description of the cell. Thus, the inventory of genes, proteins and metabolites is not sufficient to finally understand the cells complexity.

 

 

 

 

 

 

Todays systems biology follows two lines of attack:

(1) Implementation of system theory including recording of quantitative data, mathematical modelling and simulation. Till now, this concept has mainly applied to restricted systems as for instance cellular pathways, programs or compartiments. Due to these facts this modus operanti may still be viewed as a classical bottom-up concept.

(2) Network-based description of living systems. This approch has strongly improved our knowledge about the general architecture of cellular networks and has proven to be valuable in defining cellular modules. Nevertheless, the network approch is still limited in deciphering defined cellular functions and processes.