There has been an amendment to Unit 13: Forensic Genetics. In the summary of unit information under Learning Aim B in the recommended assessment approach the term organic extraction has been removed and replaced with ‘extraction of DNA’ this should now read:
- A report of essential components of a DNA extraction with an observation record to validate the practical work carried out on the extraction of DNA.
Under the content section of Unit 13 Learning aim B1 specification bullet points 2 and 3 should read:
- Essential components of a DNA extraction procedure (maximise DNA recovery, remove inhibitors, remove or inhibit nucleases, maximise the quality of DNA).
- Methods of extraction and the reagents involved (including removal of proteins by extracting aqueous solutions of nucleic acids).
The requirement for phenol and chloroform extraction method has been removed in line with safety guidance we have received.
Under the essential information for assessment decisions for Unit 13 the word organic has been removed, this should now read;
- For merit standard, learners will consider why DNA may need to be extracted and how this affects the choice of extraction technique. They will describe all the techniques in the content and provide a comparative assessment to show the appropriateness of a technique in a particular context. Individual observation records should be used to evidence the skilful extraction of DNA, with emphasis on pipetting techniques and use of centrifuge. Learners will describe errors that can occur at each stage of the PCR process and use this to explain the importance of regulation of PCR. Learners should consider and include the effects of not regulating factors such as the temperature stages, anti-contamination procedures and reagents on resulting profiles. The extent to which they are important and how they interrelate must be discussed.
- For pass standard, learners must use examples from the content to explain processes to extract genetic material from cells. Apparatus and reagents should be referred to. Learners will use two or more examples of biological material. Along with evidence generated by learners, for example lab notes and photos, individual observation records should be used to evidence the competent extraction of DNA. The level of competency can be assessed according to accurate use of equipment and reagents, demonstrating good laboratory practice and competent use of laboratory equipment. Learners will carry out PCR and use the outcomes to demonstrate understanding of the stages of PCR and explain why DNA samples need to be amplified. Learners will refer to quantity of samples required for certain types of analysis (RFLP restriction fragment length polymorphism versus STR analysis) and the destruction of DNA samples by certain modes of analysis.
This amendment is live from September 2023. If you have begun delivery of Unit 13 you may continue with delivery of the current version of the specification. For those centers that have not begun delivery of unit 13, we would suggest using the most recent edition of the specification. Centers must ensure that learners are prepared and assessed against the appropriate version of the specification.
Please ensure that all previous copies of the specification are disregarded when appropriate.
Kind regards,
Becky Thorn
Product Manager Applied Science and Sustainability
