‘Omic’ research

Introduction The neologism ‘omics’ is a collective term for a relatively new field of biology which characterises and quantifies the hierarchy of the molecules that make up any given cell, tissue or organism. This holistic view of cellular processes encapsulates the genome (genomics), mRNA (transcriptomics), proteins (proteomics) and metabolites (metabolomics). This is also referred to as ‘high-dimensional biology’, and the integration of these techniques is called ‘systems biology’. There is a useful introduction to systems biology at www.systemsbiology.org/about/what-is-systems-biology/. The basic concept of a systems biology approach is that complex organic systems can be better understood if considered as a whole. In this way, omic experiments differ from traditional research investigations, which are largely hypothesis-driven or reductionist, with a narrow focus. By contrast, systems biology experiments are hypothesis-generating, using holistic approaches where no hypothesis is known or assumed. Instead, all data possible are acquired and analysed to define a hypothesis or, more commonly, multiple hypotheses. This kind of approach has, in the recent past, been dismissed as a ‘fishing expedition’ by some, but as the field has matured and the approach has yielded valuable scientific discoveries and insights, some of which are mentioned below, a renewed appreciation of the potential power of systems biology has led to increased interest and funding. There are now numerous centres of research excellence devoted to the pursuit of systems biology throughout the world. This chapter contains an overview of the various omic disciplines and describes how they interrelate. The different components of a systems biology approach, including study design, sample preparation, the variety of technologies and platforms used for sample analysis and the challenges presented by data analysis, are reviewed. Finally, clinical examples of recent successes are provided to illustrate the potential of this field and the research approach. Omics Hierarchy Genomics Genomics is the systematic study of an organism’s genome: the complete set of DNA within a single cell of an organism and stored on 23 chromosome pairs. The haploid human genome occupies a total of just over 3 billion DNA base pairs, which results in 6 billion base pairs per diploid cell.