System biology is the new name of an old topic whose name was physiology, historically the sudy of organism was based on two main lines: anatomy that was executed on corpses and thus deals with statical structures, and physiology that was studied on living organisms and has to do with RELATIONS DYNAMICALLY LINKING the different parts of organisms. After many years in which biology only dealt with anatomy (what is the gene responsible for..) now (eventually) understood the very interesting things are in the relations between parts.

To approach systems biology I suggest a very in depth mediation on multivariata data analysis (PCA, Cluster Analysis), complex network concepts and descriptors, and havinh a taste for thermodynamics and generally energetics of biosystems, all in all what was the basic formation of a biologist/ecologist in the forties.

Alessandro is quite correct. A very good place to start is (and note the date):

Alex B. Novikoff, "The Concept of Integrative Levels and Biology", Science, New Series, Vol. 101, No. 2618. (Mar. 2, 1945), pp. 209-215.

If you google the title you might find a copy on the net.

--bks

Dear Osvaldo Martin, Alessandro Giuliani and Bradley Sherman, thankyou for your valuable suggestion.

Could you please tell me how to start this approach using specific example

You could start from any specific problem you have sufficient large data set to work with, an example could be to study the mutual correlations between gene expression profiles (based on the same kind of chip thus having the same eleemnts in terms of ORF's) of different tissues. These correlations computed over thousands of genes will give you an immediatae metrics (between pairs of tissue distances) in terms of

d(i,j) = 1 - r(i,j)where r(i,j) = Pearson correlation coefficient between tissue i and tissue j profiles. Having obtained this distances data for all the pairs you can apply on the distance matrix a multidimensional scaling procedure and look at how the tissues distribute in a synthetic space keeping trace of their mutual similarities in expression and checking iof the axes of this space correlate with embriologycal origin of the tissues (ectoderm, mesoderm, endoderm) or with some other functionally relevant property.

What are the sources, constituents and mechanics of the extracellular matrix in bacterial biofilms?

--bks