301. A reference VNTR profile from a biological stain is compared with three samples.
| Sample | Detected VNTR bands |
|---|
| Reference | P, Q, R, S, T |
| Sample X | P, Q, R, S, T |
| Sample Y | P, Q, R, T |
| Sample Z | P, R, S, T, U |
Which conclusion is justified from the fingerprint pattern alone?
ⓐ. Sample Y must come from the same source because most bands match
ⓑ. Sample Z proves that its donor produced the biological stain
ⓒ. Sample X matches the reference profile at all displayed VNTR bands
ⓓ. Sample X proves every biological characteristic of the reference donor
Correct Answer: Sample X matches the reference profile at all displayed VNTR bands
Explanation: DNA-fingerprint comparison depends on the combined pattern of polymorphic bands rather than on one or two matching fragments. Sample X matches the reference at every displayed band, so it is consistent with the same inherited VNTR profile at the loci represented by this analysis. Sample Y lacks S, while Sample Z differs through both a missing Q band and an additional U band. A matching fingerprint is strong evidence of profile consistency, but the wording must remain limited to what the molecular pattern establishes. The profile does not reveal every biological characteristic of the donor, and by itself it does not establish how or why biological material reached a particular location. Interpretation should separate molecular matching from claims that require additional evidence.
302. Two unrelated individuals share one VNTR band at a particular position, but their complete multi-band profiles differ at several other positions. What is the most appropriate interpretation?
ⓐ. A single shared band is insufficient to make the full fingerprints identical
ⓑ. The individuals must be monozygotic twins because one band matches
ⓒ. Any matching VNTR band proves that both DNA samples came from the same person
ⓓ. Different bands elsewhere can be ignored once one shared band is detected
Correct Answer: A single shared band is insufficient to make the full fingerprints identical
Explanation: A DNA fingerprint is interpreted from the combined pattern produced by several polymorphic regions. Two people can share an allele or fragment size at one VNTR locus without having the same overall profile. The discriminatory power comes from considering multiple variable loci together, so differences elsewhere in the pattern remain biologically important. One shared band provides only limited evidence of common variation at that locus and cannot establish overall identity. Classical fingerprinting is especially useful because VNTR regions are highly polymorphic and their combined pattern is characteristic of an individual, apart from the important monozygotic-twin limitation. The correct reasoning moves from one-locus similarity to whole-pattern comparison rather than treating any local match as sufficient evidence of complete profile identity.
303. Consider the following statements about VNTR band patterns.
I. Different VNTR loci can contribute several bands to a fingerprint.
II. The combined pattern can be highly characteristic of an individual.
III. Monozygotic twins are expected to have different inherited VNTR profiles at every locus.
IV. A fingerprint compares selected polymorphic regions rather than sequencing every nucleotide in the genome.
ⓐ. I and III only
ⓑ. II, III and IV only
ⓒ. I, II and III only
ⓓ. I, II and IV only
Correct Answer: I, II and IV only
Explanation: Classical DNA fingerprinting examines highly polymorphic repetitive regions such as VNTR loci, and several such regions can contribute to the final autoradiographic pattern. Combining information across multiple variable loci creates a profile that is highly characteristic of an individual. The technique does not require sequencing every base in the genome; it focuses on selected regions whose inherited variation is especially informative. Statement III is incorrect as monozygotic twins originate from the same zygote and are expected to share the inherited DNA profile used by this classical principle. That exception places a clear limit on individual discrimination. The fingerprinting method is powerful precisely as a relatively small set of highly variable genomic regions can generate substantial identifying information.
304. Classical VNTR-containing restriction fragments are described as spanning approximately \(0.1\text{–}20\,\text{kb}\). Four fragments have the following sizes: P \(0.08\,\text{kb}\), Q \(0.6\,\text{kb}\), R \(18\,\text{kb}\), and S \(24\,\text{kb}\). Which pair lies within the stated range?
ⓐ. P and Q
ⓑ. Q and R
ⓒ. R and S
ⓓ. P and S
Correct Answer: Q and R
Explanation: The stated interval begins at approximately \(0.1\,\text{kb}\) and extends to about \(20\,\text{kb}\). Fragment Q at \(0.6\,\text{kb}\) lies above the lower boundary and well below the upper boundary. Fragment R at \(18\,\text{kb}\) also lies within the interval. P at \(0.08\,\text{kb}\) is below the stated lower value, while S at \(24\,\text{kb}\) is above the stated upper value. The numerical range describes the approximate sizes of VNTR-containing fragments considered in classical VNTR-based fingerprinting. Fragment size by itself does not establish individual identity; its fingerprinting value comes from inherited polymorphic differences and comparison of the combined band pattern across samples.
305. A child's VNTR bands are M, N, P, R, S and T. The mother's bands are M, P, R and U. Candidate fathers have the following profiles.
| Candidate | VNTR bands |
|---|
| Father P | N, Q, V, W |
| Father Q | N, S, T, V |
| Father R | Q, S, U, V |
Which candidate is consistent with supplying all child bands not accounted for by the mother?
ⓐ. Father P
ⓑ. Father Q
ⓒ. Father R
ⓓ. None of the candidates
Correct Answer: Father Q
Explanation: The child's bands M, P and R are already represented in the mother's profile. The remaining child bands that require a paternal source are N, S and T. Father Q contains all three of these bands, so his profile is consistent with the inheritance pattern displayed. Father P provides N but lacks S and T, while Father R contains S but lacks N and T. The analysis does not require every paternal band to appear in the child, since a parent can possess alleles that are not transmitted to that particular offspring. The key requirement is that each child band should be explainable through inheritance from one of the biological parents at the polymorphic loci represented by the fingerprint.
306. In a disputed-paternity analysis, every VNTR band in the child that is absent from the mother's profile is present in the alleged father's profile. What is the strongest conclusion justified by this observation alone?
ⓐ. The alleged father must be the only male in the population with such bands
ⓑ. The fingerprint establishes every aspect of the family relationship beyond doubt
ⓒ. The child's nonmaternal bands arose independently and are unrelated to inheritance
ⓓ. The alleged father fits the paternal contribution at the displayed markers
Correct Answer: The alleged father fits the paternal contribution at the displayed markers
Explanation: Parentage analysis uses the inheritance of polymorphic DNA markers. Bands in the child that are not explained by the mother's profile should be compatible with the biological father's profile. If the alleged father contains all of those nonmaternal bands, his DNA pattern is consistent with the paternal contribution expected at the displayed VNTR markers. This is an evidence-based inclusion statement, not a claim that the fingerprint alone proves every aspect of parentage with no possibility of additional considerations. DNA profiles should be interpreted according to the information they directly provide. The pattern supports genetic compatibility between the alleged father and child, while stronger conclusions depend on the total marker set, population context and the complete evidence available in the actual investigation.
307. Assertion: Classical VNTR-based DNA fingerprinting may fail to distinguish monozygotic twins.
Reason: Monozygotic twins originate from the same zygote and are expected to share the inherited polymorphic DNA pattern used by this fingerprinting principle.
ⓐ. Both Assertion and Reason are true, and Reason correctly explains Assertion
ⓑ. Both Assertion and Reason are true, but Reason does not correctly explain Assertion
ⓒ. Assertion is true, but Reason is false
ⓓ. Assertion is false, but Reason is true
Correct Answer: Both Assertion and Reason are true, and Reason correctly explains Assertion
Explanation: Classical fingerprinting relies on inherited polymorphic DNA markers. Monozygotic twins develop from the same original zygote, so the inherited genomic pattern examined at these loci is expected to be essentially the same for both individuals. The reason explains the limitation stated in the assertion. This exception is important because the technique is often described as producing an individual-specific pattern, but that wording needs the monozygotic-twin qualification. The limitation does not make fingerprinting generally unreliable. Instead, it defines a biologically predictable case in which two distinct people share the same inherited marker profile under the principle being tested. Recognising this exception prevents overstatement of the technique's power. The Reason explains the limitation directly: common origin from one zygote means the inherited VNTR alleles being compared are ordinarily the same in the two twins.
308. Blood containing nucleated cells and a hair follicle are collected independently from the same person. Assuming adequate DNA quality and analysis of the same inherited VNTR loci, what pattern is expected?
ⓐ. Blood must show a maternal profile while the hair follicle shows a paternal profile
ⓑ. Each tissue should generate a completely unrelated VNTR pattern
ⓒ. The two samples should produce the same inherited VNTR profile at all tested loci
ⓓ. Only the hair follicle can contain DNA suitable for fingerprinting
Correct Answer: The two samples should produce the same inherited VNTR profile at all tested loci
Explanation: Different nucleated tissues of one individual generally contain the same inherited nuclear DNA sequence at the polymorphic loci used for fingerprinting. Blood samples provide nuclear DNA through nucleated cells such as white blood cells, while a hair follicle can also supply nucleated cellular material. When the same VNTR loci are analysed successfully, the resulting inherited profile should correspond across the two tissues. Tissue type changes the biological source of the DNA, not the person's germ-line-derived marker pattern. This is why fingerprinting can use diverse biological materials, including blood, hair follicles, skin, bone, saliva-associated cells and sperm. Adequate DNA quality and appropriate sampling remain necessary, but the inherited profile is not normally tissue-specific.
309. Samples are collected from one individual and analysed successfully at the same fingerprinting loci.
| Sample | Source | Expected inherited VNTR profile |
|---|
| P | Buccal cells in saliva | Profile X |
| Q | Skin cells | ? |
| R | Bone cells | ? |
| S | Hair follicle cells | ? |
What should replace the question marks under the stated conditions?
ⓐ. Q = Y, R = Z, S = W
ⓑ. Q = X, R = Y, S = Z
ⓒ. Q = Y, R = X, S = Y
ⓓ. Q = X, R = X, S = X
Correct Answer: Q = X, R = X, S = X
Explanation: The polymorphic fingerprint pattern is inherited as part of the person's nuclear genome and is not ordinarily reset according to whether the DNA came from skin, bone, buccal cells or a hair follicle. If the same loci are examined successfully and the samples truly come from the same individual, the expected VNTR profile should be X in all four sources. The table tests tissue consistency rather than merely listing acceptable specimens. Fingerprinting can compare DNA obtained from different biological materials precisely because the relevant inherited genomic variation is shared across the person's nucleated cells. Differences in sample type can affect DNA quantity or quality, but they do not create a new germ-line VNTR genotype for each tissue.
310. A biological trace contains only a very small amount of DNA, insufficient for the older direct fingerprinting procedure. A PCR-supported approach now permits successful analysis of the relevant polymorphic loci. What improvement is illustrated?
ⓐ. PCR changes the person's inherited VNTR alleles into more variable forms
ⓑ. PCR increases sensitivity, allowing smaller DNA samples to be analysed
ⓒ. PCR proves that every biological sample came from one person
ⓓ. PCR removes the need for polymorphic markers
Correct Answer: PCR increases sensitivity, allowing smaller DNA samples to be analysed
Explanation: The important change is analytical sensitivity. Classical fingerprinting required sufficient DNA to carry out restriction digestion, separation, blotting, probing and detection. PCR-supported methods can make analysis possible when only a very small amount of target DNA is available, allowing biological traces that would previously have been insufficient to provide useful profile information. The method does not change the person's inherited polymorphism or eliminate the need to analyse variable genomic regions. It improves the ability to obtain detectable information from limited material. For fingerprinting, the relevant consequence is increased analytical sensitivity: a smaller starting sample can yield enough target DNA for marker detection without changing the inherited marker sequence.
311. Equal very small DNA samples are tested under two conditions.
| Treatment | Polymorphic profile recovered? |
|---|
| P. Classical direct analysis without amplification | No clear profile |
| Q. PCR-supported analysis before marker detection | Clear profile |
Which inference is best supported?
ⓐ. PCR causes VNTR alleles to mutate into detectable forms
ⓑ. Classical fingerprinting cannot analyse DNA from any biological sample
ⓒ. PCR can recover profile information from very small DNA samples
ⓓ. The clear profile proves that treatment Q changes the donor's genome
Correct Answer: PCR can recover profile information from very small DNA samples
Explanation: Both treatments begin with the same very small amount of DNA, so the important difference is the use of PCR-supported analysis in Q. A clear profile after that treatment, compared with an inadequate profile from the unamplified sample, supports the conclusion that amplification improves sensitivity when starting material is scarce. The result does not indicate that the inherited alleles were altered. A useful fingerprint must reflect the donor's original polymorphic DNA rather than newly created mutations. The experiment also does not imply that classical approaches are universally incapable of analysing biological samples; they can work when sufficient suitable DNA is available. The evidence specifically concerns the advantage of PCR-supported analysis under low-input conditions.
312. Assertion: PCR-supported DNA fingerprinting can permit analysis of much smaller biological samples than older direct methods often required.
Reason: Increasing the amount of target DNA available for marker detection can make a small starting sample analytically usable.
ⓐ. Both Assertion and Reason are true, and Reason correctly explains Assertion
ⓑ. Both Assertion and Reason are true, but Reason does not correctly explain Assertion
ⓒ. Assertion is true, but Reason is false
ⓓ. Assertion is false, but Reason is true
Correct Answer: Both Assertion and Reason are true, and Reason correctly explains Assertion
Explanation: The Assertion is true: PCR-supported approaches improve the sensitivity of DNA-profile analysis and can make very small biological samples useful for examining polymorphic loci. The Reason is also true and supplies the relevant explanation. A sample may contain too little target DNA for direct detection by an older method; increasing the amount available for analysis can make the marker signal detectable. This practical gain concerns sensitivity, not a change in the individual's inherited alleles. The amplified material should represent the same target sequence information that was present in the original sample. The Reason directly connects limited starting material with successful marker detection, so it explains the Assertion rather than merely stating an unrelated advantage. DNA fingerprinting still depends on comparing inherited polymorphic regions; PCR support changes how little starting DNA may be sufficient for that comparison.
313. Which set contains only applications of DNA fingerprinting based on inherited polymorphic DNA?
ⓐ. Forensic comparison, paternity testing, population-diversity and genetic-diversity studies
ⓑ. Forensic comparison, paternity testing, direct measurement of transcription rate and genetic-diversity studies
ⓒ. Paternity testing, population-diversity studies, complete genome sequencing and direct measurement of translation rate
ⓓ. Forensic comparison, genetic-diversity studies, determination of every gene's function and measurement of replication speed
Correct Answer: Forensic comparison, paternity testing, population-diversity and genetic-diversity studies
Explanation: DNA fingerprinting compares inherited polymorphic DNA patterns. This makes it useful in forensic investigations where biological samples are compared, in disputed-paternity analysis where inheritance of marker alleles is evaluated, and in studies of variation within or among populations. The same underlying principle also supports broader assessment of genetic diversity. These applications all depend on detectable genomic polymorphism and comparison of marker patterns. DNA fingerprinting does not directly measure transcription, translation or replication rates, and it does not by itself determine the function of every gene or provide a complete genome sequence. The defining analytical question is whether inherited DNA variation can distinguish or relate samples, individuals or populations. Applications that require measuring gene expression, protein synthesis or genome-wide sequence content involve different kinds of evidence and cannot be substituted for marker-based fingerprint comparison.
314. A crime-scene profile is compared with three individuals.
| Profile | VNTR bands |
|---|
| Crime-scene sample | P, Q, R, S, T, U |
| Individual X | P, Q, R, S, T, U |
| Individual Y | P, Q, R, S, T, V |
| Individual Z | P, Q, R, W, X, Y |
Which conclusion stays within what the fingerprint alone supports?
ⓐ. Individual X is proven to have committed the crime
ⓑ. Individual Y is the source because five of six bands match
ⓒ. Individual X is consistent with the displayed crime-scene DNA profile
ⓓ. Individual Z can be identified as a close relative from these bands alone
Correct Answer: Individual X is consistent with the displayed crime-scene DNA profile
Explanation: Individual X shares every displayed VNTR band with the crime-scene sample, making X consistent with the DNA profile represented in the table. Individual Y differs at one displayed band, while Z differs at several positions. The molecular comparison can include X and distinguish the other shown profiles. It cannot, by itself, establish that X committed a crime. A DNA match addresses the relationship between a biological sample and a genetic profile, whereas culpability depends on additional contextual and investigative evidence. This boundary separates a laboratory source-comparison inference from legal or behavioural conclusions. Fingerprinting is powerful for source comparison, but its interpretation must remain limited to claims supported by the genetic pattern.
315. A DNA profile recovered from an object matches a person's VNTR profile at every locus examined. Which additional claim is not justified by that match alone?
ⓐ. The two analysed profiles are highly consistent at the tested polymorphic regions
ⓑ. The matching person must have performed the act under investigation
ⓒ. The sample can be compared with the person's inherited DNA pattern
ⓓ. The matching loci provide evidence relevant to source attribution
Correct Answer: The matching person must have performed the act under investigation
Explanation: DNA fingerprinting compares biological material with inherited polymorphic marker patterns. A complete match at the tested loci can provide strong evidence that the sample is consistent with that person's DNA profile, subject to the limitations of the testing context. What the fingerprint does not establish by itself is the behaviour that produced the sample or the circumstances under which biological material reached an object. Those are separate questions requiring additional evidence. Responsible interpretation of forensic genetics keeps molecular source information separate from conclusions about action, intent or culpability. The technique answers a genetic-comparison question, not every factual question in an investigation.
316. A child has bands P, Q, R, S, T and U. The mother has P, R, T and V. An alleged father has Q, S and W but lacks U. What is the most appropriate conclusion from these displayed bands?
ⓐ. The alleged father must be the biological father since Q and S match
ⓑ. The mother's profile is invalid because she lacks Q and S
ⓒ. The child cannot inherit bands from both parents simultaneously
ⓓ. Paternity is inconsistent because child band U is unexplained
Correct Answer: Paternity is inconsistent because child band U is unexplained
Explanation: Parentage interpretation requires the child's displayed bands to be explainable through inheritance from the two proposed parents. The mother accounts for P, R and T. The alleged father can account for Q and S, but neither listed parent contains U. Under the stated VNTR inheritance model, that unexplained child band makes the proposed parental pair inconsistent with the displayed profile. Matching several paternal bands is not enough if another required child band has no source among the proposed parents. This reasoning differs from merely asking which candidate shares the greatest number of bands. The decisive test is whether the full child pattern can be accounted for by parental inheritance at the loci represented.
317. Researchers compare frequencies of several inherited VNTR alleles across human populations rather than trying to identify a particular individual. This use of fingerprinting markers is most directly related to:
ⓐ. determining the amino-acid sequence of every protein
ⓑ. studying population-level genetic diversity
ⓒ. measuring transcriptional activity of structural genes
ⓓ. identifying the origin of DNA replication
Correct Answer: studying population-level genetic diversity
Explanation: Polymorphic VNTR loci contain inherited variation that can be examined at more than one biological scale. In forensic work, the emphasis may be comparison of individual profiles. When researchers instead measure how marker variants are distributed across groups of people, the same polymorphic loci can provide information about population diversity and genetic variation. The purpose has shifted from individual identification to description of how alleles are represented within or among populations. This application does not require the markers to encode proteins or alter gene expression. Their value comes from inherited sequence variation that can be sampled and compared systematically. The same molecular property can support different biological questions depending on how the data are organised and interpreted.
318. Two populations are examined at the same VNTR locus.
| Population | Observed repeat-number variants |
|---|
| P | \(8\) only |
| Q | \(6,\ 8,\ 11,\ 14\) |
Considering only the variation shown at this locus, which population displays greater observed genetic diversity?
ⓐ. Q, because more repeat-number variants are represented
ⓑ. P, because one variant indicates greater genetic uniformity
ⓒ. Both must have identical diversity since the locus is the same
ⓓ. No comparison is possible even at the displayed locus
Correct Answer: Q, because more repeat-number variants are represented
Explanation: The evidence is restricted to the variation displayed at one VNTR locus. Population P shows only one repeat-number variant in the supplied sample, whereas population Q shows four distinct variants. Q displays greater observed variation at this particular marker. The conclusion should not be expanded into a claim about total genome-wide diversity without additional loci and sampling information. VNTR markers can contribute to population-diversity studies because their inherited repeat-number differences provide measurable allelic variation. The table demonstrates how the same type of marker used for individual comparison can also be summarised at the population level, provided the interpretation remains limited to the evidence actually collected.
319. The Human Genome Project uses polymorphic markers in genome mapping, while DNA fingerprinting uses highly variable repetitive loci for individual comparison. What principle links these two applications?
ⓐ. Both require every informative marker to encode a protein
ⓑ. Both depend on converting genomic DNA into mRNA before analysis
ⓒ. Both use sequence variation, but for different analytical purposes
ⓓ. Both determine the complete sequence of every chromosome in each individual tested
Correct Answer: Both use sequence variation, but for different analytical purposes
Explanation: Genome mapping and DNA fingerprinting both make use of inherited DNA variation, but they apply it to different biological questions. Mapping uses polymorphic markers as landmarks that help locate or track regions across the genome. Fingerprinting selects highly variable loci, especially repetitive regions, to compare DNA samples and distinguish profiles. Neither application requires the marker to encode a protein, and neither necessarily involves sequencing an individual's complete genome. The shared molecular principle is polymorphism: detectable sequence differences provide information. The analytical purpose determines how that information is used. Mapping asks where variable markers occur or how they relate to genomic positions, whereas fingerprinting asks how a selected set of variable markers compares among samples.
320. Which statement best integrates Human Genome Project mapping with classical DNA fingerprinting?
ⓐ. HGP mapping and fingerprinting are identical procedures because both use autoradiography at every stage
ⓑ. HGP mapping uses only protein-coding genes, whereas fingerprinting uses only mutations that change phenotype
ⓒ. DNA fingerprinting must first determine the entire human genome sequence before VNTR bands can be compared
ⓓ. Polymorphic DNA can serve as a genomic landmark in mapping and as an identifying marker in fingerprint comparison
Correct Answer: Polymorphic DNA can serve as a genomic landmark in mapping and as an identifying marker in fingerprint comparison
Explanation: The two applications share the biological fact that DNA sequence variation can be detected and followed, but they ask different questions. In genome mapping, a polymorphic marker functions as a landmark that helps organise or track locations within the genome. In fingerprinting, highly variable loci such as VNTR-containing repetitive regions provide a pattern that can be compared among biological samples or individuals. The same broad property, inherited sequence variation, can support both positional and identification tasks. The techniques are not identical procedures, and informative markers do not need to change protein sequence or phenotype. This integration connects the genome-scale mapping concepts of the Human Genome Project with the individual-comparison logic of DNA fingerprinting.
