The below mentioned article provides a note on systems biology.
Systems biology is a new area of biology where an organism is viewed as an assembly of integrated and interacting networks of genes, proteins and biochemical reactions, which put life into the organism. Unlike molecular biology which focus on molecules, such as sequence of nucleotides and proteins, systems biology focus on systems that are composed of molecular components.
Scope of Systems Biology:
To understand the whole system of an organism following are the keys:
1. Understanding structure of the system, such as gene regulatory and biochemical networks, as well as physical structures.
2. Understanding of dynamics of the system, both quantitative and qualitative analysis as well as construction of theory/model with powerful prediction capability.
3. Understanding of control methods of the system.
4. Understanding of design methods of the system.
Goals and Approaches of Systems Biology:
The fundamental characteristics of systems biology are embodied in data and knowledge integration, the comprehensiveness of the data acquisition, and the ability to digitalize biological output. Integrative Biology and Digital Biology may be considered synonymous.
Systems biology seeks to explain the biological phenomenon not on a gene-by-gene basis, but through the interaction of all the cellular and biochemical components in a cell or an organism. Systems biology is still in its infancy but that has to be explored and the area that we believe to be the main stream in biological sciences in this century (Fig. 23.4).
The Institutes for Systems Biology, USA; Ottawa Institute of Systems Biology, Canada, have been established to cater the needs of this new emerging discipline.
Steps in Systems Biology:
There are five simple steps to understand the systems biology :
1. Defining of input and output of a system.
2. Defining the relevant parts of the system under study.
3. Different states of inputs are used and the relationship between these states and the output are quantified.
4. The changes in system states are related to output using one of a. variety of mathematical tools, such as principal component analysis.
5. With the help of a computer, the original network map is prepared on the basis of the results of the previous experiments.
Systems Biology in Plant Science:
The entire genome sequence of Arabidopsis and rice has been published in the year 2000 and 2005 respectively. The large scale c-DNA sequencing projects are rapidly progressing for plants like Medicago, corn, wheat, soya-bean, sugarcane, poplar, etc.
Functional genomics addresses the question what is the function of all these genes? Computational biology integrates data and ultimately helps us to understand the functioning of whole biological systems.
Plant systems biology deals ‘ with the aspects like cell cycle, root development, cell death, bud formation, flower formation, leaf development, plant-microbe interactions, etc.
Each system is highly complex, and biologists now have the tools at hand to view the global behaviour of their preferred model systems and to better select the genes that are likely to play key roles in the regulation of entire processes. Furthermore, cloning of ORFs (Open Reading Frames), promoters and making of new constructs can change or improve the gene expression which may be helpful.
Significance of Systems Biology:
With the development of new tools and techniques the complex system between genes, proteins and other metabolites can be understood; they do not work in isolation, they interact among themselves in highly organized and complex ways.
Systems biology deals with these complex interactions, which may be the biosynthetic pathways or translational modifications of proteins or the signal transduction pathway leading to expression of a set of specific genes (Fig. 23.5).
For example, the immune system is not the result of a single mechanism or a set of genes; instead, the interactions of numerous genes, proteins, metabolisms and the organism’s external environment, produce immune responses to fight infections and diseases. Thus, a study of all aspects of any system in an organism makes the subject of systems biology.