Documentation Update - Sequences Displayed in Probe Sequence Sheets (MLPA Probemixes)
We recently updated our probe sequence sheet template to display partial probe sequences in place of the full sequences. In the updated documentation, 20 nucleotides on either side of the probe's ligation site are displayed. This update is being gradually rolled out to all products. During the transition period, some products might still display the full sequences while others will display the updated partial sequences. Genomic coordinates have also been adjusted to match the new borders of displayed sequences.
Any observed changes in the sequences and the genomic coordinates of probes included in a probemix that has not had a new product version released recently, will likely be due to this documentation update and not due to an actual change in the probes' full sequence. If partial sequences are displayed, this will be made clear by:
- The words 20 nt sequence in brackets in the LPO and RPO column headers (see image above).
- A bullet point in the notes section at the top of the probe sequence sheet that says: "The sequences provided are the partial target sequences. LPO is the 5' half of the probe, RPO is the 3' half of the probe."
This change helps make the documentation across our product catalogue more uniform and consistent while at the same time providing sufficient information for reporting purposes. According to the HGVS guidelines, the preferred way of reporting copy number variations detected with MLPA is is to use the position of the nucleotide 3' of the ligation site of a probe, which therefore does not require access to the entire probe sequence but rather only the sequences adjacent to the ligation site.
If you have any questions, including whether the presence of a certain single nucleotide variant (verified for instance by sequencing) in the vicinity of a certain probe's ligation site is expected to affect the hybridization of the probe, please contact our team of Technical Support Specialists by emailing info@mrcholland.com.