What is index dropout?
In Illumina sequencing, indexing (barcoding) is the process of adding unique tags to each read in a specific sample. The indexing step is performed during library preparation after the genomic fragmentation step. After fragmentation, each…
What is the FastQ file naming convention?
When your FastQ files are delivered, you will notice they have a specific file name pattern. This is due to the naming requirements we must abide by for our bioinformatics software. In order to determine which of your samples is which, reference…
What is the read length for short-read genome sequencing?
We use an Illumina MiniSeq for our short-read sequencing runs. The paired-end short read lengths are always 2 x 150bp = 300bp. The library prep protocols are designed to fragment DNA into 150bp reads, and paired-end read runs combine two…
What are paired-end reads?
Many sequencing library preparation kits include an option to generate so-called "paired-end reads". In "short-read" sequencing, intact genomic DNA is sheared into several million short DNA fragments called "reads". Individual reads can…
What is sequencing coverage?
Coverage is defined as the number of sample nucleotide bases sequence aligned to a specific locus in a reference genome. The easiest way to explain this is with a real sequenced bacterial sample that has been aligned to the reference genome…
What is multiplex sequencing?
Some researchers may only have one or two samples that need to be sequenced. However, with the price of consumables and facility overhead, sequencing a single sample is often cost-prohibitive in normal sequencing lab settings. Multiplex sequencing…