How to read the generic genomics of microbial genomes

2017-08-03 22:16:22 GMT+0800

In 2005, American scientists Tettelin in the study of group B streptococcus, first put forward the concept of genome-wide, points out that there are significant differences between different strains of bacteria, the single strain of genetic information is not complete on behalf of the all the genetic information.
Bacteria genome-wide analysis can comprehensively to study the genetic diversity of bacteria, explore the evolution of the relationship between different individuals and to the discovery of important virulence factors, and the new vaccine design has important application value.

The generic genome can be divided into three parts, the core genes, the accessory genes and the specific genes.
The core genome is the gene that all strains share, and these genes are involved in basic biological processes, such as gene expression, energy generation, amino acid metabolism, etc.
Accessory genes refer to genes in some strains that are related to the diversity of species and give individuals a competitive advantage.
Specific gene exists only in a certain strains, these genes are generally through the level of gene transfer (HGT) and is often associated with special phenotypic characteristics of the strain, such as the specific environment of adaptability, or unique pathogenicity, etc.

Below to share an article recently published in the use of genome-wide studies of different populations of streptococcus pneumoniae genome-wide Heterogeneity of literature and core genome: Heterogeneity among estimates of the core genome and pan - genome in company's pneumococcal populations.

The authors studied 3121 pneumococcal bacteria from healthy individuals from four regions of the world (Reykjavi k, South ampton, Boston, Maela).

The core genomic comparison of data sets in 4 regions

Reykjavik (n = 1,059), Southampton (n = 1,052), Boston (n = 1,029), the number of core genomes in these three regions is similar, and the number of core genes in Maela is only 394.
But 4 core set COG in the genome function distribution similar: the highest proportion is unknown function gene (21.7 24.1%), and, in turn, is the translation, the ribosome structure and biosynthesis (11.9 15.7%), amino acid transport and metabolism (7.1 8.6%), transcription (6.7 7.9%).