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. 

aCGH workflow

A sample (embryo biopsy) is placed into a PCR tube and enzymatically lysed.
WGA amplifies the genome millions of times.

The reference sample is labelled with red fluorescent dye.

The test sample is labelled with green fluorescent dye.

The test and reference are combined on the microarray surface and they compete for binding positions.

After microarray scanning and data analysis, the relative fluorescence signals of the test and the reference are compared.

This EmbryoCellect™ result was generated from a single fibroblast from a male cell line with trisomy for chromosomes 16 and 21 (48,XY,+16,+21).

EmbryoCellect™ is for research use only and not for use in diagnostic procedures.