Andrew Severin

Andrew Severin

His PhD was in Biophysics/NMR spectroscopy. He did a Bioinformatics Postdoc in Soybean genetics and now runs the Genome Informatics Facility at Iowa State University. He is passionate about evolution and the science behind the genome. There is so much we don't know about how the elements in a genome interact to create the fine balance of gene expression, modification and 3D structure that create the dynamic range of phenotypes we observe. As sequencing technology continues to improve and the cost continues to decrease, we will be able to ask more complex questions that increase our understanding via comparative and translational genomics.

Funding and Cost

Most research has a strict allowance for how much sequencing and bioinformatics can be performed to answer the biological question of interest. An understanding of the following terminology can aid in determining the type and amount of sequencing that is best suited for your biological purpose.

  • Short Read
    • Read length:Short reads (50bp) are difficult to align to unique locations in a genome, so unless the experiment is for smRNA it is uncommon to use very short reads.
    • Paired-end Both ends of the DNA fragment are sequenced. This type of sequencing is useful for obtaining more unique alignments to a genome For RNA-Seq experiments with a known genome, it is recommended to use at least 100bp paired-end Illumina data. For RNA-Seq experiments without a genome or a genome of questionable quality, it recommended to use 150bp Illumina paired-end data.
    • Single-end Used when the experiment has DNA fragments shorter than the length of the read. For example, smRNA experiments are typically done with 50bp single-end data.
    • Long Read Long reads are mainstream now for genome assemblies and are becoming mainstream in RNA-Seq, 16S studies and can be combined with single cell techniques *
  • Biological Replicates It is extremely important to have at least 3 replicates and preferably 5 to 10 replicates for RNA-Seq experiments to determine differential expression

Examples

In the next sections we will go over several example experimental design problems from real world examples.

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