Microbial Genomics
2021-08-04
- 16S/18S/ITS Amplicon Sequencing
- Metagenomic Shotgun Sequencing
- Metatranscriptomic Sequencing
- Microbial Whole Genome Sequencing
16s rRNA gene, a highly conserved component, is the most widely used gene marker for genus and species identification and taxonomic significance in bacteria and archaea. 16S rRNA gene sequencing has become prevalent in microbiology as a rapid and cheapalternative to phenotypic methods of bacterial identification. Although it was originally used to identify bacteria, 16S sequencing was subsequently found to be capable of reclassifying bacteria into completely new species, or even genera. It has also been used to describe new species that have never been successfully cultured.
18S rRNA is commonly used in fungi for phylogenetics since it has more hypervariable domains than 16S. In addition to this, the ITS (internal Transcribed Spacer) region (including 5.8S), removed in the post transcriptional process of nuclear rRNA cistron, has been widely regarded as a universal fungi barcode marker for a successful identification for the broadest range of fungi. And compared to 18S, ITS is more variable and hence more suitable as the genetic marker for measuring intra specific genetic diversity.
16S/18S/ITS Amplicon Sequencing has now been awell-established method for microbial identification and phylogeny studies of samples from complicated microbiomes or environments. In addition tonext-generation sequencing platforms, Jenker also provides full-length16S/18S/ITS amplicon sequencing by using PacBio SMRT sequencing technology.
Advantages of 16S/18S/ITS Amplicon Sequencing
- The most common housekeeping genetic markers with conserved and variable regions.
- Characterized by fast speed, cost-efficiency and high-precision.
- Multiple applications: microbial identification, diversity analysis, taxonomy and
- Phylogeny, new species determination, relationship study of microorganism and disease, metagenomics, etc.
- Data quality control
- OTUs cluster and phylogenetic relationship construction
- Species annotation
- Alpha diversity analysis
- Beta diversity analysis
- ...
Analysis workflow
Metagenomic shotgun sequencing targets the entirety of the microbial genetic information contained in an environmental sample. The obtained community taxonomic profile can be further associated with the functional profile of known and unknown organism lineages. The complete sequences of protein-coding genes and full operons in the sequenced genomes can offer invaluable functional knowledge about the microbial communities inhabiting practical ecosystems under study. Metagenomic shot gun sequencing may provide genetic information on potentially novel biocatalysts orenzymes, genomic linkages between function and phylogeny for uncultured organisms, evolutionary profiles of community function and composition and much more.
Advantages of Metagenomic Shotgun Sequencing
- Ction-independent
- Cost-effective,and time-efficient
- Provide comprehensive information on community biodiversity and function
- Data quality control
- Assembly
- Species annotation
- Gene prediction
- Gene annotation
- Species/Gene/Function abundance statistics and cluster analysis
- Comparative analysis
- ...
Analysis Workflow
Metatranscriptomics is the culture-independent profiling (including protein-coding and non-coding DNA) of microbial community-wide gene expression, which is capable of monitoring RNA-based regulation and expressed biological signatures of complex bacterial communities in a given sample at a given moment and under specific conditions. Itelucidates three aspects of a microbial community, including gene activity diversity, gene expression abundance, and differential gene expression analysis. The gene expression analysis can tell which genes exhibit the highest change in expression levels in different conditions potentially to identify biomarkers and expression signatures.
Advantages of Metatranscriptomic Sequencing
- Aculture-free method to reveal the true extent of microbial diversity
- Permittingfunction-based activity screens
- Moretargeted than shotgun random sequencing
- Cost-efficient and time-effective
- Data quality control
- Statistics analysis of data production and quality
- De novo assembly
- Gene functional annotation
- rRNA& mRNA taxonomic analysis
- Gene expression analysis
- Differential expression analysis
- GO enrichment analysis of differentially expressed genes (DEGs)
- KEGG pathway enrichment analysis of differentially expressed genes(DEGs)
- Comparative analysis between various samples
- ...
Analysis Workflow
Microbial whole genome sequencing is important for precise microbial identification, the generation of complete reference genomes (de novo sequencing), comparative genomic studies (re-sequencing), and genomic exploitation. Comparative genomic studies can identify individual genetic variations and large-scale structural variations within a population for which a reference genome is available. Evolutionary characteristics and phylogenetic relationships can be hence inferred. Microbial whole genome sequencing provides the possibility of gene finding and annotation. After multiple genes are explained, novel biochemical pathways that may be beneficial for medicine and biotechnology will likely be identified.
Advantages of Microbial Whole Genome Sequencing
- A time-effective and cost-efficient approach
- Broad applications: de novo sequencing, gene annotations, comparative genomic studies, evolutionary studies of micro-organisms, etc.
- Drug discovery and development: assess the contribution of DNA on pathogenesis, and understand the role of elements in drug resistance and transmission
For de novo
- Data quality control
- Genome advanced assemble
- Genome survey: genome size, GC distribution, repeat rate
- Genome component analysis: gene structure prediction, repeat sequences, non-codingRNAs
- Gene function annotation
- Data quality control
- Alignment with reference
- SNP/InDel calling, annotation and statistics
- SVcalling, annotation and statistics