Indian Journal of Medical Microbiology Home 

EDITORIAL
Year : 2001  |  Volume : 19  |  Issue : 3  |  Page : 114--115

Impact of human genome sequencing on microbiology

SE Hasnain 
 Centre for DNA Fingerprinting and Diagnostics (CDFD), ECIL Road, Nacharam, Hyderabad - 500 076, India

Correspondence Address:
S E Hasnain
Centre for DNA Fingerprinting and Diagnostics (CDFD), ECIL Road, Nacharam, Hyderabad - 500 076
India

How to cite this article:
Hasnain S E. Impact of human genome sequencing on microbiology.Indian J Med Microbiol 2001;19:114-115

How to cite this URL:
Hasnain S E. Impact of human genome sequencing on microbiology. Indian J Med Microbiol [serial online] 2001 [cited 2020 Nov 26 ];19:114-115
Available from: https://www.ijmm.org/text.asp?2001/19/3/114/8142

Full Text

The human society is overburdened with infectious diseases, the prominent ones being Tuberculosis and Malaria. Despite worldwide efforts towards prevention and cure of these deadly infections, they remain major causes of human morbidity and mortality. The last couple of decades have seen the application of molecular genetic approaches for studying various aspects of infectious diseases. Perhaps, the most important development has been the concerted efforts to determine the genome sequence of important human pathogens. The complete genome sequence of M.tuberculosis was released in June, 1998. Efforts are currently underway to sequence genomes of P.falciparum, P.vivax etc. The genome sequence of the pathogen provides us with the complete list of genes and through functional genomics, a potential list of novel drug targets and vaccine candidates can be identified.

Any successful strategy for combating a particular infection must have a two pronged approach viz. study of the pathogen and study of the host factors. While the study of pathogens is very important, the contributions of the host in promoting or containing infection(s) cannot be ignored. An important example is the failure of the widely publicised BCG vaccine trial in the Chengalput area of Tamilnadu. This result made TB researchers to sit up and take note of the importance of the host genetic components. The genetic variation inherent in the human population can modulate success of any vaccine or chemotherapeutic agent. This is why, the sequencing of the human genome has not only attracted interest of all those working on human genetic disorders but also of scientists working in the field of infectious diseases.

The elucidation of the human genome sequence will have a tremendous impact on our understanding of the prevention and cure of infectious diseases. This will be possible through efforts in areas such as structural genomics, pharmacogenomics, comparative genomics, proteomics, and most importantly, functional genomics. Functional genomics not only includes understanding the function of genes and other parts of the genome, but also the organization and control of genetic pathway(s). There is an urgent need to apply high throughput methodologies such as Microarrays, Proteomics (the complete protein profile of a cell as a function of time and space), and study of Single Nucleotide Polymorphisms (SNPs, pronounced as 'snips'), transgenes and gene knockouts. Microarrays have a tremendous potential in 1) determining new gene loci in disease, 2) understanding global cellular response to a particular mode of therapy, 3) elucidating changes in global gene expression profiles during disease condition, etc. The specific example of tuberculosis can be cited in this context. It is common knowledge that there are several healthy contacts in an endemic population. Studies have identified several host genetic factors that may be involved in conferring protection to this population. These may include iron scavenging proteins, interferon gamma receptors etc. Microarrays can be used to determine host genetic factors by studying gene expression profiles of macrophages infected with clinical isolates of M.tuberculosis.

The emergence of the discipline pharmacogenomics is a consequence of the human genome project. It is common knowledge that different people react differently to common drugs. Sometimes, this can be attributed to specific changes in the genes involved in the activation of the drug in question. This is an important area of study termed Single Nucleotide Polymorphisms (SNPs). SNPs are the most common form of genetic variation, which occur once every 500-1000 bases and may predispose people to disease or their response to drugs. SNPs are now increasingly being used to determine drug toxicity by analyzing the drug metabolizing enzymes, the optimum dose, drug efficacy, and determining adverse drug reactions. For using SNPs as diagnostic markers, it is important to prune the background SNPs in order to identify the specific SNP implicated in a specific type of cancer. This can be possible only by the study of a large number of subjects. Such markers for diseases will be useful in determining when to treat a patient; for monitoring treatment; and to evaluate efficacy of new treatments. Genomics will usher in a future where the patient carries his 'gene profile card', determined by microarrays, to the doctor, who is then able to determine which drug to prescribe and also the dose of the drug. The sequencing of the human genome thus promises to totally revolutionize the way medicine will be practised in the coming years.