DNA Profiling and Forensic Biology — MCQs

Q: Which of the following sources provides the highest yield and most reliable samples for DNA fingerprinting?

Blood. ***Blood*** - **Blood** provides a high concentration of **nucleated cells** (e.g., white blood cells), yielding abundant and high-quality DNA. - The DNA obtained from blood is typically well-preserved and less prone to degradation or contamination compared to other sources. *Saliva* - While saliva contains DNA from **buccal epithelial cells** and white blood cells, its DNA yield can be lower and more variable due to mucous and bacterial contamination. - DNA from saliva may be more subject to degradation, especially if not collected and stored properly. *Tooth* - **Teeth** can be a good source of DNA, particularly from the **pulp**, but extraction can be challenging and destructive. - The DNA yield varies depending on the tooth's condition and the extraction method, and it is generally reserved for situations where other sources are unavailable or severely degraded. *Buccal mucosa* - **Buccal mucosa** swabs are a common and non-invasive source of DNA from **epithelial cells**. - While suitable for many applications, the DNA yield can be lower than blood, and the sample may be more susceptible to surface contamination.

Q: Who invented the technique for identifying individuals by their DNA?

Jeffreys. ***Jeffreys*** - **Alec Jeffreys** developed the technique of **DNA fingerprinting** in 1984, which revolutionized forensic science and paternity testing. - His method involved analyzing **variable number tandem repeats (VNTRs)** in DNA to create a unique profile for each individual. *Shapiro* - **Robert Shapiro** is a legal figure, famously associated with the O. J. Simpson murder trial, not directly with the invention of DNA identification techniques. - While he was involved in cases where DNA evidence was used, he did not contribute to its scientific development. *Lewis* - **Edward B. Lewis** was a Nobel Prize-winning geneticist known for his work on **developmental genetics** in *Drosophila melanogaster*, not for DNA identification techniques. - His research focused on gene clusters and their role in embryonic development. *Pasteur* - **Louis Pasteur** was a pioneering microbiologist and chemist, famous for his discoveries related to **vaccination**, microbial fermentation, and pasteurization. - His work predates the discovery and application of DNA for individual identification by over a century.

Q: Which of the following is NOT a screening test for blood?

Takayama crystal test. ***Takayama crystal test*** - The **Takayama crystal test** (also known as the **hemochromogen crystal test**) is a **confirmatory test** for blood, not a screening test. - It identifies the presence of **hemochromogen crystals** formed from hemoglobin, providing a more definitive positive result. *Leucomalachite green test* - The **leucomalachite green test** is a **presumptive screening test** for blood, relying on the peroxidase activity of hemoglobin. - A positive result indicates the possible presence of blood and requires further confirmatory testing. *Phenolphthalein test* - The **phenolphthalein test** (also known as the **Kastle-Meyer test**) is a **presumptive screening test** for blood, also based on hemoglobin's peroxidase activity. - It produces a rapid color change in the presence of blood, suggesting its presence but not definitively confirming it. *All of the options are screening tests* - This statement is incorrect because the **Takayama crystal test** is a **confirmatory test**, distinguishing it from screening tests. - Screening tests provide a preliminary indication, while confirmatory tests offer a more conclusive identification.

DNA Profiling and Forensic Biology — MCQs

Practice by Chapter

DNA Structure and Function

Practice Questions

DNA Extraction Methods

Practice Questions

PCR Technology

Practice Questions

Short Tandem Repeat Analysis

Practice Questions

Y-STR and Mitochondrial DNA

Practice Questions

DNA Databases

Practice Questions

Population Genetics in Forensics

Practice Questions

Statistical Interpretation

Practice Questions

Body Fluid Identification

Practice Questions

Bloodstain Pattern Analysis

Practice Questions

Emerging DNA Technologies

Practice Questions

Quality Assurance in DNA Testing

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free

Scan to download app