Whole Genome Amplification (WGA)
Typically only a few or even a single cell are used for pre-implantation genetic screening (PGS). A single human cell contains approximately 6 picograms (6x10-12 grams) of DNA that needs to be reliably amplified (copied) millions of times to obtain enough DNA for screening.
This process, which is termed whole genome amplification (WGA), is performed using a specialised type of polymerase chain reaction (PCR) that amplifies a large diverse range of sequences scattered across all chromosomes in the cell (genome). One method used for WGA is Degenerate Oligonucleotide Primed (DOP) PCR, which uses a large number of primers that can bind to many sequences across the genome and initiate amplification. The robustness and fidelity of the WGA is very important , as any errors introduced by this process may affect the accuracy of the results. RHS have used advanced PCR polymerases to optimise the DOP-PCR WGA in EmbryoCellect™.
Lane 1 contains a DNA size marker ladder, lanes 2-5 are DOP-amplified single cells, lanes 6-9 are 30pg genomic DNA amplified templates and lane 10 is a no template control where no DNA was added to the reaction, Lane 11 is a DNA Ladder
Array Comparative Genomic Hybridisation (aCGH)
aCGH is used to determine the number of chromosomes in a sample by comparing the relative amount of flouresence of the sample to a known reference.