Key Components

1. Sample Collection: Meta-transcriptomics begins with the collection of environmental samples. These samples are often complex, containing a wide range of microorganisms.

2. RNA Extraction: RNA is extracted from the sample, which includes mRNA, rRNA, tRNA, and other non-coding RNAs. This step is crucial as it determines the quality and representativeness of the data.

3. Sequencing: High-throughput RNA sequencing (RNA-seq) technologies are used to obtain sequences of the RNA transcripts. This step provides a vast amount of data on the RNA molecules present in the sample.

4. Data Analysis: Computational tools and bioinformatics methods are employed to process and analyze the sequencing data. This involves mapping RNA sequences to reference genomes or transcriptomes, identifying expressed genes, and quantifying their abundance.

5. Functional Annotation: The functional roles of identified transcripts are inferred based on known gene functions, allowing researchers to understand the metabolic and ecological functions of the microbial community.

Applications

1. Environmental Monitoring: Meta-transcriptomics can be used to monitor the health and functional status of ecosystems. For example, it can help assess the impact of pollution on microbial communities by revealing changes in gene expression related to stress response and degradation processes.

2. Microbiome Research: In human health, meta-transcriptomics offers insights into the gut microbiome’s functional state. It helps in understanding how microbial communities interact with their host, how they respond to dietary changes, and their role in health and disease.

3. Biotechnology: The technique can aid in the discovery of novel enzymes and bioactive compounds by profiling microbial communities in extreme environments or industrial processes.

4. Disease Pathogenesis: By analyzing RNA profiles from disease-associated environments, researchers can uncover pathogen-host interactions and identify potential targets for therapeutic interventions.

Challenges

1. Complexity of Data: The sheer volume and complexity of data generated by meta-transcriptomics can be overwhelming. Effective data management and advanced computational tools are required to extract meaningful insights.

2. Sampling Bias: Environmental samples can be heterogeneous, and RNA extraction methods may introduce biases, potentially affecting the accuracy of the results.

3. Reference Databases: Incomplete or biased reference databases can hinder the accurate functional annotation of transcripts, especially when studying novel or poorly characterized organisms.

Future Directions

Meta-transcriptomics is a rapidly evolving field, with ongoing advancements in sequencing technologies and bioinformatics. Future research may focus on improving data integration, developing more comprehensive reference databases, and enhancing our understanding of microbial community dynamics in various environments. As these challenges are addressed, meta-transcriptomics will continue to provide valuable insights into the functional roles of microorganisms and their interactions within ecosystems.

Conclusion

Meta-transcriptomics represents a powerful tool for exploring the functional aspects of microbial communities in their natural environments. By capturing a snapshot of gene expression and metabolic activities, this approach offers a deeper understanding of ecological interactions, health implications, and biotechnological potentials. As technology and methodologies advance, meta-transcriptomics is poised to make significant contributions to our knowledge of the microbial world.

[Download software package (includes the manual)] (you will be directed first to a registration page and we would very much appreciate if you register) 
[Download manual] 
[Download software note from Molecular Ecology Notes 4: 137-138 (2004)]

To use the UNIX versions, unzip and untar the files in an appropriate directory using

gunzip filename.tar.gz; tar xvf filename.tar

where "filename.tar.gz" is the downloaded file. Winzip will unzip the Windows version. Run the program by typing

./distruct

in UNIX or

distruct

from a Dos prompt in Windows. It will produce a figure using the data that are represented in the Central/South Asia K=5 plot in Science 298: 2381-2385 (2002).

Please send comments or problems with distruct to Noah Rosenberg.

October 15, 2014 — Users of Distruct may also find CLUMPP and CLUMPAK of interest.

Address of the bookmark: https://rosenberglab.stanford.edu/distruct.html

install.packages("devtools")
#It may be necessary to install required as not all package dependencies are installed by devtools:
install.packages(c("dplyr","tidyr","ggplot2","MASS","meta","ggrepel","DT"))
devtools::install_github("PheWAS/PheWAS")
library(PheWAS)

Address of the bookmark: https://github.com/PheWAS/PheWAS

More at https://github.com/snakemake/snakemake-wrappers

Address of the bookmark: https://snakemake-wrappers.readthedocs.io/en/stable/

https://github.com/ncbi/JUDI

Address of the bookmark: https://github.com/ncbi/JUDI

Address of the bookmark: https://zpicture.dcode.org/

heatmaply also provides an interface based around the plotly R package. This interface can be used by choosing plot_method = "plotly" instead of the default plot_method = "ggplot". This interface can provide smaller objects and faster rendering to disk in many cases and provides otherwise almost identical features.

Documentation for this package is also available as a pkgdown site: http://talgalili.github.io/heatmaply/

Address of the bookmark: http://talgalili.github.io/heatmaply/articles/heatmaply.html

Address of the bookmark: https://github.com/snakemake-workflows/dna-seq-gatk-variant-calling

• data = mock data for the snakefile to use
• Snakefile = name of the snakemake “formula” file
  • Note: The default file that snakemake looks for in the current working directory is the Snakefile. If you would like to override that you can specify it following the -s
    • snakemake -s snakefile.py
• envs = directory for storing the conda environments that the workflow will use.
• scripts = directory for storing python scripts called by the snakemake formula.
• config.json = json format file with extra parameters for our snakemake file to use.
• cluster.json = json format file with specification for running on the HPC
• samples.txt = file we will use later relating to the config.json file.

Run the snakemake file as a dry run (the example workflow shown above).

• This will build a DAG of the jobs to be run without actually executing them.
• snakemake --dry-run

User can execute rules of interest.

• snakemake --dry-run all VS. snakemake --dry-run call VS. snakemake --dry-run bwa

Run the snakemake file in order to produce an image of the DAG of jobs to be run.

• snakemake --dag | dot -Tsvg > dag.svg OR snakemake --dag | dot -Tsvg > dag.svg

Run the snakemake (this time not as a dry run)

1. snakemake --use-conda

Prerequisites

This is an intermediate lesson and assumes learners have already done some bioinformatics:

• Familiarity with the BASH command shell, including concepts like pipes, variables and loops.
• Knowledge of bioinformatics fundamentals like the FASTQ file format and transcriptome sequencing, in order to understand the example workflow.

No previous knowledge of Snakemake or workflow systems is required.

https://carpentries-incubator.github.io/snakemake-novice-bioinformatics/index.html

Address of the bookmark: https://carpentries-incubator.github.io/snakemake-novice-bioinformatics/aio/index.html