11 And now for our genetic tests

There are many hundreds of possible DNA variants in the gene. The reagents available in this PCR laboratory test for the CYP2D6*4 variant and test for gene copy number.

The location of each primer pair for the two genetic tests you will be performing is shown in Figure 7. The region containing the *4 variant (as was detailed in Figure 4), is amplified using one pair of primers (Figure 7, left of exon 4, running into exon 4). This test amplifies the presence of the CYP2D6 *4 only. The overall CYP2D6 gene copy number is detected using a pair of primers located in exon 9 (Figure 7, right). This test amplifies all variants of the gene, acting solely to indicate the gene copy number but providing no information about whether any particular DNA variant is present.

Figure 7 Location of the PCR primers being used within the CYP2D6 gene. Amplification of the CYP2D6 gene by PCR in genomic DNA can be followed by real time analysis of fluorescence. Detection of the point at which amplified DNA levels cross a set threshold is automatically detected. © The Open University

Show description|Hide description

Location of the PCR primers being used within the CYP2D6 gene. Amplification of the CYP2D6 gene by PCR in genomic DNA can be followed by real time analysis of fluorescence. Detection of the point at which amplified DNA levels cross a set threshold is automatically detected.

Figure 7 Location of the PCR primers being used within the CYP2D6 gene. Amplification of the CYP2D6 gene by PCR in genomic DNA can be ...