Forensic Genetics Quiz: DNA Analysis and Applications

Why can bone tissue preserve DNA over time?. Continuous hydration in Haversian canals. Low residual vascularization reduces turnover. Mineralization acts as a physical-chemical barrier. High activity of endogenous nucleases in the long term.

Which part of the tooth is most suitable for recovering nDNA from degraded remains?. Enamel. Root cementum. Dental pulp. Surface dentin.

What is the primary function of the extracellular matrix (ECM)?. Regulates cell behavior (mechanical/biochemical signals). Always inhibits proliferation and differentiation. Is an inert filler with purely mechanical function. Is present only in epithelial tissue.

What is the correct order of biological hierarchy useful for trace analysis?. Cell → Tissue → Organ → System/Apparatus. Organ → Cell → Tissue → System. Cell → Tissue → System → Organ. Tissue → Organ → Cell → System/Apparatus.

In blood, the nuclear DNA (nDNA) useful for profiling primarily comes from: Erythrocytes. Hemoglobin. Leukocytes. Platelets.

In an isolated hair: The shaft provides abundant nDNA. The bulb contains only mtDNA. The shaft offers more RNA than DNA. The anagen bulb provides nDNA; the shaft often only mtDNA.

What characterizes 'Touch DNA'?. Influence of friction/duration/substrate; frequent partial profiles and mixtures. Sweat as the primary source of DNA. Absence of indirect transfer. Complete profiles from abundant nucleated cells.

In buccal swabs, what is the primary source of nDNA?. Desquamated epithelial cells. Oral bacteria. Salivary amylase. Acellular saliva.

What do trace nature tests establish?. Individual identity. The date of the trace. The nature of the material, not 'whose it is'. A substitute profile for typing.

Which characteristics correctly describe epithelial tissue?. Abundant ECM, spaced cells, slow turnover. Abundant ECM, rapid turnover, but no basement membrane. Scarce ECM, juxtaposed cells, frequent turnover. Scarce ECM, sparse cells, no turnover.

Which factors most significantly influence the yield of Touch DNA?. Friction/duration of contact. Type of substrate. Environmental conditions. All of the other answers are correct.

Which blood component contains the main quantity of nDNA useful for profiles?. Erythrocytes. Platelets. None of the other answers. Plasma.

Which base is present in RNA in place of thymine?. Cytosine. Adenine. Guanine. None of the other answers.

What components constitute a DNA nucleotide?. Deoxyribose + phosphate + nitrogenous base. Ribose + phosphate + uracil. Ribose + phosphate + nitrogenous base. Deoxyribose + two phosphate groups + nitrogenous base.

In which direction does synthesis catalyzed by polymerases occur?. 3' to 5' for DNA polymerase. 5' to 3' for both. Depends on the target gene. 3' to 5' for RNA polymerase.

Why are the major and minor grooves of the double helix relevant?. Because they expose chemical patterns read by proteins without opening the helix. Because they favor thermal denaturation of DNA. None of the other answers. Because they impede access of regulatory proteins.

What is the preferred choice if nDNA is highly fragmented?. Sequencing the portion of the genome of interest. Y-STR. Standard STR with long amplicons. miniSTR or SNP with short amplicons.

Which statement about nDNA and mtDNA is correct?. nDNA: linear, biparental; mtDNA: circular, maternal, multi-copy. Both are circular and maternal. mtDNA always has a greater discriminating power than nDNA. nDNA: circular; mtDNA: linear.

Which function-molecule pairing is correct?. mRNA: catalysis; rRNA: messenger; tRNA: ribosome. mRNA: messenger; rRNA: catalytic core of ribosome; tRNA: adapter. mRNA/rRNA/tRNA have the same function. mRNA: adapter; rRNA: transports amino acids; tRNA: messenger.

What factors degrade the analyzability of DNA in forensic samples?. Heat/UV and oxidation. Extreme humidity/pH and mechanical stress. Endogenous/microbial DNases. All of the other answers are correct.

Which step is part of the maturation of eukaryotic mRNA?. Assembly of ribosomal subunits. Telomeric elongation. Methylation of genomic DNA. Addition of the 5' cap.

Which statement about the genetic code is correct?. It is not redundant: one amino acid has only one codon. It varies between tissues in the same individual. It is ambiguous: the same codon codes for multiple amino acids. It is redundant/degenerate but not ambiguous.

What function do telomeres serve?. Protect chromosome ends, preventing fusion and inappropriate repair. Facilitate centromere pairing. None of the other answers. Activate transcription of nearby genes.

What is a-satellite DNA...?. A centromeric LINE. A peritelomeric SINE. None of the other answers. A centromeric tandem repeat.

Which group does interspersed repetitive DNA belong to?. Microsatellites (STR). LINE-1, SINE/Alu, LTR/ERV. a-satellite. Minisatellites (VNTR).

Where is a-satellite DNA mainly located, and what is its key role?. Subtelomeres; protection against fusion. Promoters; direct transcriptional control. Centromeres; scaffold for the kinetochore and microtubule attachment. Pericentromeres; meiotic recombination.

What advancement did the T2T consortium bring in 2022 compared to the 2003 reference?. Complete sequence without gaps (including centromeres), with error correction. First draft of the human genome. Closure of the mtDNA. Reduction of the number of genes to <10,000.

What practical benefits arise from knowledge of genomic architecture in various applications?. All of the other answers are correct. Targeted therapies in oncology. Diagnosis/pharmacogenomics in clinics. Choice of STR/SNP panels in forensics.

Which statement about STRs is correct?. They are located exclusively within genes. No answer is correct. They are repeats of 2-6 bp, highly polymorphic, with tetranucleotides preferred. They are repeats of 10-20 bp, highly polymorphic, with trinucleotides preferred.