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Table of Contents

Your Instructors

Most of us are members (or alumni) of the functional genomics lab of Vishwanath Iyer, UT Austin.

  • Anna Battenhouse

    , Associate Research Scientist, Iyer Lab

    , abattenhouse@utexas.edu,
    Biomedical Research Computing Facility Manager, and Marcotte lab staff

    • BA English literature, 1978

    • Commercial software development 1982 –

      2005

      2007

    • Joined Iyer Lab 2007 (“retirement career”)

    • BS Biochemistry, UT Austin, 2013

  • Amelia Weber Hall, Graduate Student, Iyer Lab, ameliahall@utexas.edu
    • 5th year Microbiology graduate student
    • Laboratory Technician at UT 2007-2010
    • BS Molecular Genetics, 2007
  • Nathan Abell, Research Assistant, Xhemalce Lab, abell.nathan@gmail.com
    • Undergraduate researcher in Iyer Lab 2011-2013
    • BS Molecular Biology, UT, 2013
    • Research Assistant
  • Dakota Derryberry, Graduate Student, Wilke Lab, dakotaz@utexas.edu
    • ???

...

    • Joined the Biomedical Research Computing Facility (BRCF) and Marcotte Lab 2017
    • Also affiliated with
  • Matt Bramble, matthew.bramble@austin.utexas.edu,
    Associate Research Scientist, Bioinformatics Consulting Group
    • Master’s degrees from UT Austin in Molecular Biology and Statistics
    • 10 years of experience with R and Python
    • Recently joined the CBRS Bioinformatics Consulting Group after six years at MD Anderson Cancer Center analyzing a wide range of NGS epigenomics data
    • Areas of expertise include: Hi-C (chromatin conformation) analysis, mouse somatic variant analysis, and single cell RNAseq analysis

About the Iyer Lab (where Anna learned NGS)

http://iyerlab.org/

Dr. Vishy Iyer, PI

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Main focus is functional genomics

    • large-scale

...

    • transcriptional reprogramming
      in response to diverse stimuli
    • Encode consortium collaborator

...

    • works in human and yeast


Research methods include
  • microarrays (Dr. Iyer was co-inventor)

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  • high-throughput sequencing (since 2007)
    • especially ChIP-seq, RNA-seq
    • also

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    • miRNA-seq, RIP-seq, MNase-seq ...

...

    • >2,000 NGS datasets

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Communication

Post its

Green post-it – I'm good at the moment.

Pink post-it – I need a bit of help.

Conventions

...

Asking questions

Feel free to ask questions any time during the instructor's lecture and demonstrations.

For online attendees, you can also post your question to the Zoom chat. We'll sometimes use breakout rooms when troubleshooting problems you run into, if so, TA Matt Bramble will assign you to one.

Getting help

Since most folks are new to the Linux command line, we expect you to run into problems! Please let us know if you're having difficulties!

Making mistakes and running into problems is key to learning the Linux command line! It is not only expected – it is encouraged (smile).

Conventions

If you see a block of text like this:

Code Block
languagebash
titleExample code block
ls -h

it means, "type the command ls -h into a terminal window, hit return Enter, and see what happens".

We intend this course to offer as much self-learning as possible. Consequently, you'll find many sections like this - click on the triangle to expand them:

Expand
Hint
titleHint...

Hint sections will provide you some guidance on what to do next, but will not spell it out.

and some sections like this:

Expand
Solution
titleSolution...

Solution sections will contain the commands so that you could copy-and-paste them if you have to. They should be exactly accurate.

Goals and challenges

will represent one method of answering the question – but there are often many ways to skin a cat!

Course goals

  • Hands-on, tutorial style – learn by doing
    • Common bioinformatics tools & file formats
  • Introduce NGS vocabulary
    • both high-level view and practice with specific tools
  • Cover the NGS tool basics – the
    • The first few things you'll do after receiving raw sequences
      • raw sequence QC and preparation
      • alignment to reference
      • basic alignment analysis
  • Understand and practice required skills
    • Get you comfortable with Linux and TACC – your best "frenemies"
    • Make you self-sufficient enough in
    4
    • 5 days to become experts over time
    • Show some "best practices" for working with NGS data

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NGS Challenges

Diverse skill set requirements

  • Analysis – making sense of raw data
    • one part bioinformatics and statistics
    • one part scripting / programming
      • Linux command line
      • High Performance Computing (TACC)
      • bash scripting (grep, awk)
      • R, python, perl
  • Management – making order out of chaos
    • one part organization
    • one part data wrangling
  • Adoption of best practices is critical!
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Large and growing datasets

NGS methods procude produce staggering amounts of data!

Typical dataset these days

  • yeast:  5 – 20 million reads
  • human:  20 – 100 250 million reads (~5 - 8 million for TagSeq)
  • single end (SE) or paired end (PE), length 75 50 100 bases300 bases (100 or 150 typical)

The initial fastq FASTQ files are big (100s of MB to GB) – and they're just the start.

  • Organization and naming conventions are critical.
  • Your data can get out of hand very quickly!

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Progression of Iyer Lab

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datasets over time:

...

  • 2008 – Yeast heat shock remodeling of chromatin
    • 2 yeast datasets
    • less than 2 million readssequences
  • 2010 – Allelic bias in CTCF binding
    • 13 CTCF datasets from 3 GM cell lines
    • ~200 million readssequences
  • 2012 – Analysis of Transcription factor data analysis (ENCODE2)
    • 32 ChIP-seq datasets gathered over 3 years (3 TFs across 11 cell lines
    • 32 datasets gathered over 3 years
    • ~ 1 billion reads
    2014 – QTL
    • )
    • ~ 1 billion sequences
  • 2013 – miRNA overexpression effects
    • 42 RNAseq datasets (7 conditions)
    • ~ 2.6 billion sequences
  • 2014 – eQTL analysis of CTCF binding
    • 52 very deeply sequenced CTCF datasets
    • ~ 8 billion readssequences
  • in progress 2018 – Functional analysis of glioblastoma tumors and cell lines
    • > 300 datasets so far
    • > 17 billion reads

Data wrangling best practices summary

keep fastq files compressed

  • Most sequencing facilities will give you compressed sequencing data files
    • gzip format (.gz extension) for individual files
    • tar or zip format for directories of files
  • Even with compression it's easy to run out of storage space!

You may be tempted un-compress your sequencing files to manipulate them more directly

  • resist the temptation to gunzip!
  • nearly all modern bioinformatics tools are able to work on .gz files
  • there are techniques for working with compressed files without ever un-compressing them

arrange adequate storage space

  • Obtain an allocation on TACC's corral disk array (initial 5 TB are no-cost)
  • Stage your active projects on corral 
    • copy data to $WORK or $SCRATCH for analysis
    • copy important analysis products back to corral 
  • Periodically back up corral directories to ranch tape archive

backup analysis artifacts regularly

  • Obtain an allocation on TACC's ranch tape archive system
    • 10 TB a good initial number
    • free! and under-utilized
  • Periodically back up your corral directories to ranch tape archive

distinguish between types of data

Artifacts from different stages of the analysis will have different archival requirements.

  • Original sequence data (fastq files)
    • must be backed up!
  • Alignments
    • usually larger than original fastqs
    • should be backed up once stable
  • Peak calling artifacts
  • Downstream analysis artifacts

While a project is active you will want to keep more intermediate artifacts for reference. Many of these can be deleted after publication.

track your analysis steps

Your analyses should be reproducible by others so you need to keep the equivalent of a lab notebook to document your protocols.

    • nearly 500 datasets in total (ChIP-seq, RNAseq, miRNAseq, 4C, exome/genome sequencing)
    • > 22 billion sequences