Bioinformatics Core

General Questions

What experimental variables may affect my second generation sequencing or microarray experiments?

  • Sample collection and nucleic acid isolation. All variables that you do not want to study should remain the same. In other words, samples should be collected at the same time of day, the same amount of time after watering or feeding.
  • DNA and RNA concentration and quality should be checked on a reliable spec. We have a NanoDrop Spectrophotometer available to read low volumes. Make sure the amount of starting material is the same for every library or chip in the experiment. We also have a Qubit fluorometer for quantifying low concentrations of nucleic acids.  For next generation sequencing library quantification we recommend Q-PCR quantification with the KAPA Library Quant Kit.
  • Using different technicians, equipment and a variety of reagent lots may also affect your results.

How many replicates should I use in my microarry experiment?

  • You should have at least 3 replicates per each experimental group. The more replicates you have the better statistical power.

About Analysis

What software do I need to align Illumina reads to reference sequences in my own lab?

  • You can use commercial software such as CLCbio Workbench or open source software such as BWA and Bowtie2 (all available on HPC3 accessible to UCI researchers).

How do I get an account on UCI's High Performance Community Computing Cluster (HPC3)?

  • If you are affiliated with UCI, you can get an account on HPC3 for free. See OIT's HPC3 webpage for details.

What software do I need to de novo assemble illumina reads in my own lab?

  • For genome assembly, you can use commercial software such as CLCbio Workbench or open source software such as ABySS, Velvet and ALLPATHS (all available on HPC). For de novo transcriptome assembly, Trans-AByss, Velvet-Oases and Trinity can be used. For reference-based transcriptome assembly, StringTie is recommended.

What software do I need to analyze illumina reads from RNA-Seq in my own lab?

  • You can use commercial software such as CLCbio Workbench or open source software such as Hisat2 and STAR to align your reads and StringTie or Salmon, (all available on HPC3) to do transcript assembly, featureCounts and Salmon for abundance quantification and DESeq2 differential expression. Differential expression statistical analysis can also be done with R packages such as edgeR, DESeq

Where can I find the shared genome index on HPC?

  • You can find the shared prebuilt genome index files for mouse and human on HPC3 at /data/apps/commondata/.

How do I interpret the columns in the differential expression analysis in DESeq2?

  • col2: log2 fold change (MAP): condition treated vs untreated
  • col3: standard error: condition treated vs untreated
  • col4: Wald statistic: condition treated vs untreated
  • col5: ald test p-value: condition treated vs untreated
  • col6: BH adjusted p-values that controls FDR(false discovery rate)

What free software do you recommend viewing my alignment data?

Can I reanalyze my data using other software programs?

  • Yes – Our data are in standard format (BAM/SAM, FASTA/FASTAQ, BED, VCF, WIG etc.) and can be viewed and analyzed using a variety of software that accept standard input.

Can I view my data in the UCSC genome browser?

How do I get gene annotation information?

What other software programs can be used for downstream statistical data analysis?

  • R and Python (available on HPC3).

     

What text editor programs do you recommend?

Do you have information about NIH guidelines for data sharing and security?

What commercial software do you recommend for further analysis of gene expression data such as pathway analysis?

What open source software do you recommend for further analysis of gene expression data such as pathway analysis?

About IPA

Where can I learn more about Ingenuity Pathways Analysis (IPA)?

Licensed IPA Users have access to customer Support team (PhD Scientists) via phone and email M-F 6am to 5pm PST.

Customer Support:  (650) 381-5111 | support@ingenuity.com

Quality Control

How much sample volume do I need to bring for QC?

For typical QC including nanodrop/ qubit and bioanalyzer, it would be best to bring at least 5 uL. However, if you require additional QC services, such as Kapa qPCR, then you would need to provide more sample volume. We can always return the leftover samples when we are done with QC.

Can I get my samples back after QC?

Yes, just write on the order form that you would like us to keep the leftover samples. However, unless otherwise noted, samples will need to be picked up within 1 month after project completion.

What if I need Bioanalyzer results as soon as possible?

If you need results as soon as possible, you have the option of paying to run a full chip, which means that in addition to paying for your samples you will also have to pay for all the empty wells on that chip. Each chip has 11 wells.

For example, if you have 4 DNA samples to run on a DNA high sensitivity chip, burning a chip means that you will have to pay for 11 samples (4 DNA samples + 7 empty wells).

How are the samples run on the Bioanalyzer?

We normally dilute the samples to the appropriate loading concentration range for the type of bioanalyzer run:

  • DNA HS – up to 0.7 ng/uL by qubit reading
  • RNA Nano – up to 500 ng/uL by nanodrop reading
  • RNA Pico – up to 5 ng/uL by nanodrop reading

What is the difference between RNA Pico Bioanalzyer and RNA Nano Bioanalyzer?

The major difference between the Pico and Nano assay is the quantitative range. RNA Pico has a quantitative range of 50-5000 pg/uL. While RNA Nano has a quantitative range of 5 – 500 ng/uL. Also, the RNA Pico chip processes 11 samples at time, while the RNA Nano processes 12 samples at a time.