Sample interview questions: Can you discuss the process of comparative analysis in forensic biology?
Sample answer:
Comparative analysis in forensic biology plays a crucial role in identifying and comparing biological evidence from crime scenes and suspects. It is a systematic process that involves several steps:
- Sample Collection and Preservation:
- Biological evidence, such as blood, saliva, semen, or hair, is carefully collected from crime scenes and suspects using appropriate techniques.
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The samples are then properly packaged and preserved to maintain their integrity and prevent contamination.
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DNA Extraction:
- DNA is extracted from the collected samples using specialized techniques, such as phenol-chloroform extraction or silica-based DNA extraction kits.
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This process isolates DNA from other cellular components, allowing for further analysis.
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Quantification and Quality Assessment:
- The amount of DNA in each sample is quantified using methods like spectrophotometry or real-time PCR.
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The quality of the extracted DNA is also assessed to ensure its suitability for further analysis.
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Amplification:
- The DNA is amplified through a process called PCR (Polymerase Chain Reaction).
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PCR makes multiple copies of specific regions of DNA, generating enough material for subsequent analysis.
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Genetic Profiling:
- Specific genetic markers, such as short tandem repeats (STRs), are targeted for analysis.
- STRs are polymorphic regions of DNA that exhibit variations among individuals.
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PCR amplification of these STR loci generates a unique genetic profile for each sample.
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Data Analysis:
- The amplified STR fragments are separated and detected using capillary electrophoresis or other DNA analysis techniques.
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The resulting data is analyzed using specialized software to determine the alleles present at each STR locus.
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Comparison:
- The genetic profiles generated from crime scene evidence are compared to those obtained from suspects o… Read full answer