DNA Testing in Sexual Offences — MCQs
Which test is most sensitive for detecting semen in forensic investigations?
A 28 year old victim of gang rape is brought to you for examination. Which of the following test would you NOT expect to be positive in a sample material obtained from the victim's vagina?
Doctor or nurse disclosing the identity of a rape victim is punishable under the following section of IPC?
Restriction fragment length polymorphism is used for:
Which of the following is a primarily RNA based technique?
Which of the following is used to detect abnormal gene sequences EXCEPT?
From a medico-legal perspective, in cases of sexual assault involving a female victim, what type of court proceeding is typically used to record medical evidence and testimony to protect the victim's privacy?
DNA amplification is done by all, except:
Anal coitus with opposite sex is -
Rape is defined under:
DNA Testing in Sexual Offences Indian Medical PG Practice Questions and MCQs
Question 1: Which test is most sensitive for detecting semen in forensic investigations?
- A. Luminol test
- B. Acid phosphatase test (Correct Answer)
- C. Barberio test
- D. Florence test
Explanation: ***Acid phosphatase test*** - This test is highly sensitive for detecting **prostatic acid phosphatase (PAP)**, a key enzyme found in high concentrations in semen. - A positive result, indicated by a **rapid color change**, suggests the presence of seminal fluid, even in small quantities. *Luminol test* - The luminol test is used to detect **bloodstains** at a crime scene, causing them to luminescence, but it is not specific for semen. - While it can react to other substances and potentially give **false positives** for semen, its primary use is for blood detection. *Barberio test* - The Barberio test is a **confirmatory microcrystal test** for spermine, a component of semen. - It involves the formation of specific crystals; however, it is less sensitive for initial screening than the acid phosphatase test and requires the presence of spermine. *Florence test* - The Florence test is a **confirmatory microcrystal test** for choline, another component of semen. - Similar to the Barberio test, it is a corroborative test that requires the formation of specific crystals and is not used for initial, highly sensitive screening.
Question 2: A 28 year old victim of gang rape is brought to you for examination. Which of the following test would you NOT expect to be positive in a sample material obtained from the victim's vagina?
- A. Gettler's test (Correct Answer)
- B. Aluminium molybdate test
- C. Acid phosphatase test
- D. Barberio's test
Explanation: ***Gettler's test*** - **Gettler's test** is used to detect **hemoglobin derivatives**, specifically **carboxyhemoglobin** or **methemoglobin**, in blood or tissue samples, primarily for suspected carbon monoxide poisoning or specific types of poisoning. - This test is **not relevant** for the analysis of seminal fluid or vaginal swabs in cases of sexual assault. *Aluminium molybdate test* - The **aluminum molybdate test** is used to detect **choline** in seminal fluid, which is a component of semen. - A positive result suggests the presence of **ejaculated semen**, indicating recent sexual activity. *Acid phosphatase test* - The **acid phosphatase test** is a common forensic test used to detect the presence of **human prostatic acid phosphatase (PAP)**, an enzyme found in high concentrations in seminal fluid. - A positive reaction is a strong indicator of the presence of **semen** in a vaginal sample. *Barberio's test* - **Barberio's test** is a microscopic test used to detect **spermine picrate crystals**, which form when picric acid is added to seminal fluid. - This test is highly specific for the presence of **spermine**, a polyamine found in high concentrations in semen.
Question 3: Doctor or nurse disclosing the identity of a rape victim is punishable under the following section of IPC?
- A. Section 224A
- B. Section 226A
- C. Section 222A
- D. Section 228A (Correct Answer)
Explanation: ***Section 228A IPC*** - This section of the Indian Penal Code specifically deals with the **disclosure of the identity of a victim of rape and certain sexual offenses** (Sections 376, 376A, 376AB, 376B, 376C, 376D, 376DA, 376DB, 376E). - Making public the name or any matter that can reveal the identity of a rape victim by **any person, including doctors and nurses**, is a punishable offense. - **Punishment**: Imprisonment up to **2 years** and fine. - **Exception**: Disclosure is permitted only to authorized persons like police officers for investigation purposes. - **Important**: This is now covered under **Section 72 of Bharatiya Nyaya Sanhita (BNS) 2023**, which replaced the IPC. *Section 224A* - This is **not a valid or recognized provision** within the Indian Penal Code. - It does not relate to offenses concerning privacy or the identity of sexual assault victims. *Section 226A* - This is **not a valid or recognized provision** within the Indian Penal Code. - It does not pertain to the confidentiality of victims of sexual offenses. *Section 222A* - This is **not a valid or recognized provision** within the Indian Penal Code. - There is no such specific section addressing disclosure of victim identity in the IPC.
Question 4: Restriction fragment length polymorphism is used for:
- A. Detection of gene mutations
- B. Genetic mapping and identification (Correct Answer)
- C. Paternity testing
- D. Forensic analysis
Explanation: ***Genetic mapping and identification*** - **Restriction fragment length polymorphism (RFLP)** exploits variations in DNA sequences that create or abolish **restriction enzyme recognition sites**, leading to fragments of different lengths. - These polymorphic fragments serve as **genetic markers** to map genes on chromosomes and identify specific genes or genetic regions. *Detection of gene mutations* - While RFLP can detect some mutations by altering restriction sites, it is not the primary or most efficient method for general **gene mutation detection**. - Techniques like **DNA sequencing** or **PCR-based assays** are typically more sensitive and comprehensive for direct mutation analysis. *Paternity testing* - RFLP was historically used for **paternity testing** by comparing inheritance patterns of polymorphic markers between child and alleged father. - However, it has largely been replaced by more advanced and faster methods like **short tandem repeat (STR) analysis** due to higher discriminatory power and lower DNA requirements. *Forensic analysis* - Similar to paternity testing, RFLP was an early technique employed in **forensic analysis** for DNA fingerprinting to identify individuals. - Modern forensic DNA analysis predominantly uses **STR profiling**, which offers greater resolution, speed, and requires smaller, less degraded samples.
Question 5: Which of the following is a primarily RNA based technique?
- A. Western blotting
- B. Northern blotting (Correct Answer)
- C. Southern blotting
- D. Sanger's technique
Explanation: ***Northern blotting*** - **Northern blotting** is a molecular biology technique used to study **gene expression** by detecting specific **RNA molecules** (mRNA) in a sample. - It involves separating RNA fragments by **gel electrophoresis**, transferring them to a membrane, and then detecting specific sequences using **labeled probes**. *Western blotting* - **Western blotting** is a technique used to detect specific **proteins** in a sample. - It involves separating proteins by **gel electrophoresis**, transferring them to a membrane, and then detecting specific proteins using labeled **antibodies**. *Southern blotting* - **Southern blotting** is a molecular biology method used for the detection of **specific DNA sequences** in DNA samples. - It involves separating **DNA fragments** by **gel electrophoresis**, transferring them to a membrane, and then hybridizing with a labeled probe. *Sanger's technique* - **Sanger sequencing**, or the **dideoxy chain-termination method**, is a widely used method for **DNA sequencing**. - It uses **dideoxynucleotides** to terminate DNA synthesis at specific bases, allowing the determination of the **DNA sequence**.
Question 6: Which of the following is used to detect abnormal gene sequences EXCEPT?
- A. RFLP analysis
- B. Pyrosequencing
- C. Flow cytometry (Correct Answer)
- D. FISH
Explanation: ***Flow cytometry*** - **Flow cytometry** is primarily used to analyze **cell populations** based on their physical and biochemical characteristics (e.g., size, granularity, and protein expression) by passing them single file through a laser beam, not for direct gene sequencing. - It detects and quantifies cells labeled with **fluorescent antibodies**, making it useful for immunophenotyping, cell sorting, and DNA content analysis, but not for identifying specific gene sequences or mutations. *RFLP analysis* - **Restriction fragment length polymorphism (RFLP) analysis** detects variations in **DNA sequences** by using **restriction enzymes** to cut DNA at specific sites. - Differences in fragment lengths indicate **polymorphisms** or **mutations** within the recognition sites, thereby identifying abnormal gene sequences. *Pyrosequencing* - **Pyrosequencing** is a method of **DNA sequencing** that determines the sequence of nucleotides by detecting the release of pyrophosphate during DNA synthesis. - It is used to identify **single nucleotide polymorphisms (SNPs)** and **short genetic variations**, making it suitable for detecting abnormal gene sequences. *FISH* - **Fluorescence in situ hybridization (FISH)** uses **fluorescently labeled DNA probes** that bind to specific complementary **DNA sequences** on chromosomes. - It is a powerful cytogenetic technique for detecting **chromosomal abnormalities**, such as deletions, translocations, and amplifications, thereby identifying abnormal gene sequences.
Question 7: From a medico-legal perspective, in cases of sexual assault involving a female victim, what type of court proceeding is typically used to record medical evidence and testimony to protect the victim's privacy?
- A. Open court proceedings
- B. Closed court proceedings
- C. Hearing at a different location
- D. In camera proceedings (Correct Answer)
Explanation: ***In camera proceedings*** - **In camera proceedings** (Latin for "in chambers") refer to court hearings conducted in **private**, with the public and media excluded, to protect the victim's privacy and dignity. - Under **Section 327(2) of CrPC**, cases of sexual offences against women must be conducted in camera to prevent further trauma and ensure the victim can provide testimony comfortably. - This legal provision ensures **confidentiality** of victim identity and prevents public disclosure of sensitive medical evidence and testimony. - The proceedings are still officially recorded and form part of the legal record, but occur in a closed, private setting. *Open court proceedings* - **Open court proceedings** allow public and media access, which would severely compromise the victim's privacy and cause additional psychological trauma. - Such public exposure is specifically prohibited in sexual assault cases under Indian law to protect the **victim's identity** and well-being. *Closed court proceedings* - While this term might seem similar, **"closed court"** is not the standard legal terminology used in Indian jurisprudence for sexual assault cases. - The specific term **"in camera"** is used in Section 327 CrPC and judicial pronouncements, making it the precise medico-legal answer. *Hearing at a different location* - Changing the location does not inherently provide the **legal framework** for privacy protection that in camera proceedings mandate. - This option lacks the formal legal status and procedural safeguards that Section 327 CrPC provides through in camera hearings.
Question 8: DNA amplification is done by all, except:
- A. DNA sequencing (Correct Answer)
- B. Loop-mediated isothermal amplification (LAMP)
- C. Ligase chain reaction
- D. Polymerase chain reaction
Explanation: ***DNA sequencing*** - **DNA sequencing** determines the **nucleotide base order** in a DNA molecule but does not increase the amount of DNA. - While requiring a DNA template, it is an **analytical technique** rather than an amplification method. *Loop-mediated isothermal amplification (LAMP)* - **LAMP** is an **isothermal DNA amplification** technique that amplifies target DNA sequences at a constant temperature (60-65°C). - It uses a DNA polymerase with strand displacement activity and 4-6 primers to produce large amounts of DNA rapidly. *Ligase chain reaction* - **LCR** is an amplification method that detects specific **DNA sequences** by ligating adjacent probes. - It amplifies the signal from a target DNA sequence rather than the DNA itself by creating many copies of joined probes. *Polymerase chain reaction* - **PCR** is a widely used technique for **amplifying** a specific segment of DNA to produce many copies. - It involves cycles of **denaturation**, **annealing**, and **extension** using a DNA polymerase.
Question 9: Anal coitus with opposite sex is -
- A. Sin of Gomorrah
- B. Bestiality
- C. Fellatio
- D. Sodomy (Correct Answer)
Explanation: ***Sodomy*** - **Sodomy** is a historical legal and religious term for certain sexual acts deemed illicit, traditionally encompassing anal sex and bestiality. - While its legal definition varies, in common usage, it often refers to **anal coitus**, especially when involving participants of the opposite sex (heterosexual anal sex) or same sex (homosexual anal sex). *Sin of Gomorrah* - The "Sin of Gomorrah" refers to the actions of the inhabitants of the biblical cities of Sodom and Gomorrah, which are described as being wicked. - While traditionally interpreted by some as encompassing **homosexual acts and inhospitality**, it is a religious concept, not a direct term for specific sexual acts like anal coitus. *Bestiality* - **Bestiality** is a sexual act between a human and a non-human animal. - This term specifically involves animals and has no relevance to sexual activity between two human beings. *Fellatio* - **Fellatio** refers specifically to oral sex performed on a penis. - This term describes oral-genital contact and is distinct from anal coitus.
Question 10: Rape is defined under:
- A. Sec. 320 IPC
- B. Sec. 375 IPC (Correct Answer)
- C. Sec. 351 IPC
- D. Sec. 376 IPC
Explanation: ***Sec. 375 IPC*** - **Section 375 of the Indian Penal Code (IPC)** specifically defines **rape**. It outlines the various circumstances under which a sexual act is considered rape, focusing on the absence of consent. - The section has been amended several times to broaden its scope and strengthen protections for victims, particularly after significant legal reforms. *Sec. 320 IPC* - **Section 320 IPC** defines **"Grievous Hurt,"** which includes severe injuries like emasculation or deprivation of any joint or part of the body. - This section deals with the classification of serious bodily harm, not sexual offenses. *Sec. 351 IPC* - **Section 351 IPC** defines **"Assault."** It refers to making any gesture or preparation intending or knowing it to be likely that such gesture or preparation will cause any person present to apprehend that he who makes it is about to use criminal force to him. - This section addresses acts that create an apprehension of immediate criminal force, not the act of rape itself. *Sec. 376 IPC* - **Section 376 IPC** deals with the **"Punishment for Rape."** While it is directly related to rape, it specifies the penalties for the offense, not its definition. - This section lays down the various terms of imprisonment and fines that can be imposed on a person convicted of rape, including aggravated forms of the crime.
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