General information
The SALSA MLPA Probemix P200 Reference-1 is a research use only (RUO) assay which contains reference probes and control fragments specific for unique human DNA sequences. The P200 probemix offers a collection of thoroughly-tested MLPA reference probes and control fragments to which ‘home-made’ synthetic (MS-)MLPA probes can be added. Not only do these control fragments and reference probes provide extra assurance about the quality of home-made probes and of the MLPA reaction performed, they also facilitate the data analysis of your synthetic probemix and maximise the number of synthetic probes you can include.
Next to the P200, MRC Holland also offers the P300 Reference-2 probemix. While the P200 leaves the entire range from 82-173 nt open for the inclusion of synthetic probes, the P300 probemix has reference probes distributed over the whole size range of the probemix. This is especially advantageous for correction of the signal sloping of MLPA amplification products. Signal sloping is the effect that longer probes generate a lower peak height/area on the electropherogram than shorter probes; the exact amount of signal sloping differs between sequencer types and can differ between different samples and can disturb the analysis.
The use of P200 is recommended when a large number of synthetic probes are used, preferably targeting sequences on different chromosomes. Results can be difficult to interpret when P200 is used in combination with a small number of probes all targeting the same gene or chromosomal region, and with lengths much smaller than the reference probes. In samples with sloping, it may seem in such cases that all sequences targeted by the synthetic probes are deleted or duplicated. The use of P300 is recommended when a smaller number of synthetic probes is used. Please note that MRC Holland cannot offer support for custom probe design anymore.

This SALSA MLPA probemix is not CE/FDA registered for use in diagnostic procedures. Purchase of this product includes a limited license for research purposes.

Probemix content
The SALSA MLPA Probemix P200-B1 Reference-1 contains 14 MLPA probes with amplification products between 173 and 251 nucleotides (nt). This includes, ten reference probes that detect autosomal chromosomal locations. Complete probe sequences and the identity of the genes detected by the reference probes are available online (www.mrcholland.com). In addition, one DNA Denaturation fragment (D-fragment), one digestion control fragment, one chromosome X, and one chromosome Y-specific fragment are included (see Table 1). In addition, it contains four DNA Quantity fragments (Q-fragments) at 64-70-76-82 nt. Interpretation of these control fragments should be done by Coffalyser.Net analysis software. In order to let Coffalyser.Net do this correctly, a few adaptations are necessary. Information on how to make these adaptations can be found here: https://www.mrcholland.com/r/p200/coffalyser-sheet-adjustments. Information about the quality scores in Coffalyser.Net can be found in the Coffalyser.Net Reference Manual (https://www.mrcholland.com/r/ifu/coffalyser-net-reference-manual).