Summary of Bacterial Genomics and Pathogen Evolution

In the recent years, genetic field has been developed in such a fast rate, it has even infiltrated the microbiology world. Microbiology, being one of the most wonderful parts of scientific world has been greatly affected by the genetic knowledge. Genetic sequence of bacterial has started to be mapped and understood. Comparative genomic and its tools have been used to identify the unknown part of bacteria and pathogen. As time goes on, new technique on genetic mapping has replaced the old biochemical approach. This change in the genetic mapping technique has greatly affected the world of microbial genomics which in turn provide a great help to the discovery of virulence genes.

Pre and post genomic era

            Before bacterial genomic was found and mapped, attempt to discover the virulence genes has been done through the biochemical approaches which is the forward and reverse genetic screens.  The discovery of bacterial genomics has certainly facilitated the classical approach but at the same time has allowed different method of identification of virulence genes to be discovered and used. There are a few methods which have been employed to accommodate the discovery of virulence genes such as computational methods, genetic signature, physical linkage to accessory genetic element, and also biochemical and genetic approaches that depend on comprehensive genome sequence information. Practically, the main goal of genomics is to identify and define genes which are important and essential for growth or virulence. The distinction between these two categories has been unclear since genes are required for growth of organism and are also required for the growth inside a host. Various approaches have also been used to identify these essential and virulence genes. Methods such as isolating temperature-sensitive mutants, insertion-duplication mutagenesis, in-vivo expression technology, signature-tagged transposon mutagenesis and TnAraOut has been developed and now well known for the screening of these essential and virulence genes. Small and large genome which has been identified tells us on how the essential activities in the bacterial body have been carried out. These genes also tell on which environment these bacterial will be able to live in.

Microarray-Based Comparative Genomics and Expression Studies

            Microarray has been plotted as one of the powerful tools which allow an easy genomics comparison of either similar or different strains of the same or similar species. These tools allow us to compare sequenced and un-sequenced strains of the genome. Microarray has helps us to further understand the big world of evolution and pathogenesis. A lot unknown area can be explored by the help of microarray tools. Encountering a drawback is not something that we can run away from even with the most advance technique. In this case, DNA comparison only enables us to explore the missing genes in the strains but not the additional gene which an organism may have.

            Genomic sequencing has moved us a step closer to understand the genes which is essential for the growth of bacteria and pathogen. With the current knowledge, we manage to understand the genes that they need in order for them to survive in different environmental condition and also during in vivo growth. But, as we manage to understand more, more question comes up. In the recent years, we have been asking on how these genes work, what else we can explore from this vast and growing world of bacterial genome, etc.

            From this article, I have come across the various method of genome identification, starting from the classical approach to the most up to date method that we can use. All this methods contribute to more scientific field to explore. This article also tells us on the research prospect on yet to be discovered part of bacterial and pathogen world. Besides that, at the same time, it tells us that bacterial world has more information to be discovered and it has been a leading science. Technique used in the identification still has many flaws which are not fixed yet, the recent method discovered still could not reveal the hidden and unknown part of the bacterial genome that we have manage to study so far.

By: Benny

for the full text of the review article, kindly proceed to the link given below, thank you

DOI 10.1016/j.cell.2006.02.002