Tuesday, February 1, 2011



Study of comparison of two genomes of an organism is called comparative genomics.
Generally we can say that computational molecular biology is nothing but study of biology in computer. That means biology in silica. Application of computer knowledge in biology is called as computational molecular biology.
It is use full in drug discovery, enzyme discovery, in data mining exploring the data sequence, in phylogenetic analysis. It has functional genomics, structural genomics and comparative genomics.
Study of differences and similarities in genome structure and organization in different organisms.
For example how the human beings and other organisms are are related in our genomes.
And how similar are the number of proteins humans, fruit flies, plants, yeasts and bacteria.

Comparative genomics is the application of bioinformatics methods to the analysis of whole genome sequence with the objective of identifying biological principles.
Comparative genomics is extremely powerful techniques and provides biological insights that could not be achieved in any other way.


There are two different drivers in comparative genomics.
1. First one is study of grass level of evolution that how organisms has developed and the similarities between different organisms. Such that what makes the organisms look unique.
2. The second one is the need to translate the DNA sequence data into a protein of known function.

DNA sequences encoding cellular proteins are more conserved than that of non coding proteins.
Until recently it was thought that ideal species for comparison are those whom form, structure, physiology are similar as possible whose genomes whose genomes have evolved sufficiently that non functional genomes have time to diverge.


1. The minimal gene set consistent with independent existence can be determined using comparative genomics.
2. Larger microbial genomes have more paralogs than smaller microbes.
3. Horizontal gene transfer may be a significant force but it is not easy to detect.
4. The comparative genomics of closely related bacteria gives useful insights about the evolution of microbes.
5. Comparative analysis of phylogenetically diverse bacteria enables common structural themes to be uncovered. Comparative genomics can be used to analyze phylogenetical phenomena.
6. Comparative genomics can be used to identify genes and regulatory elements.
7. Comparative genomics gives insights into the evolution of key proteins.
8. Comparative genomics can be used to uncover the molecular mechanisms that generate new gene structures.

The COG must encode proteins and be found in 3 hyperthermophiles.
The number of hyperthermophiles with a particular COG should be greater than the number of mesophiles.
More than 50% of the organisms with a particular Cog should be thermophiles.

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