DNA Sequencing and DNA Profiling
DNA sequencing and DNA profiling are related technologies, but they answer different questions. Sequencing tells us the order of bases. Profiling compares patterns at selected DNA regions to infer similarity, difference and inheritance links in populations.
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Four printable worksheets that build from the foundations up to exam-style questions — start at whatever level suits you.
A student says, "DNA profiling and DNA sequencing are basically the same thing because both use DNA. If you have a DNA profile, you already know the exact base order of the whole genome."
Before reading on, explain why that statement is weak. What does sequencing determine that profiling usually does not?
Know
- What DNA sequencing determines.
- What DNA profiling compares.
Understand
- Why sequencing and profiling answer different biological questions.
- How both technologies help infer inheritance patterns in populations.
Can Do
- Distinguish base-order determination from pattern matching.
- Explain why these tools matter beyond a narrow forensic context.
Core Content
Technology 1 · reading the base order
Sequencing asks: what is the exact nucleotide order in this DNA region or genome?
If the sequence is known, specific mutations, SNPs and gene variants can be identified directly. This is powerful for investigating inherited disorders, comparing species, and analysing how populations differ at the DNA level.
Sequencing provides the base order itself, not just a comparison pattern.
What to write in your book
- DNA sequencing = determining the exact nucleotide order.
- If the sequence is known, specific mutations/SNPs/variants can be identified directly.
- Useful for inherited disorders, species comparison, population-level DNA differences.
- Gives actual base order, not just a comparison pattern.
DNA _____ determines the exact order of nucleotide bases in DNA.
Technology 2 · pattern comparison, not full reading
DNA profiling does not normally read the full base order of the whole genome. Instead, it compares patterns at selected DNA regions that vary between individuals. This allows samples to be distinguished or matched more efficiently.
What it compares
Patterns in selected marker regions rather than the entire genome sequence.
What it can show
Similarity, difference, and possible inheritance relationships between samples.
What it does not do
It does not automatically reveal the exact complete base order for the whole genome.
What to write in your book
- DNA profiling = comparing patterns at selected DNA regions that vary between individuals.
- It can distinguish or match samples efficiently.
- Shows similarity, difference, possible inheritance links.
- A profile is NOT a full genome sequence.
A DNA profile reveals the complete base order of the whole genome.
DNA profiling uses short tandem repeats (STRs) to create a unique genetic fingerprint for an individual.
DNA sequencing determines the three-dimensional structure of proteins.
Key distinction · base order vs pattern
DNA sequencing
- Determines nucleotide order
- Can identify specific mutations or SNPs directly
- Useful for variant discovery and detailed comparison
DNA profiling
- Compares selected DNA patterns
- Useful for matching or distinguishing samples
- Supports inference about relatedness or inheritance links
Both technologies can contribute to understanding inheritance patterns in populations, but the strength of the conclusion depends on what data was collected. Sequencing offers more direct molecular detail. Profiling offers efficient comparison at specific markers.
What to write in your book
- Sequencing: nucleotide order; identifies specific mutations/SNPs; variant discovery.
- Profiling: compares selected patterns; matches/distinguishes samples; relatedness.
- Both can study inheritance in populations.
- Sequencing = more detail; profiling = efficient comparison.
Which technology directly identifies a specific inherited base change?
Module 5 focus · inheritance, not just forensics
For Module 5, the important idea is not a narrow forensic storyline. The important idea is how these tools are used to investigate inheritance across groups.
Disease inheritance
- Sequencing can identify inherited variants linked to disease.
- Profiling can help compare related samples or lineages.
Relatedness and structure
- Sequencing and profiling can reveal similarities and differences between populations.
- Patterns help infer relatedness trends, not absolute certainty from one sample alone.
What to write in your book
- Module 5 focus = inheritance across groups, not just forensics.
- Sequencing identifies inherited disease-linked variants.
- Profiling compares related samples/lineages.
- Patterns infer relatedness trends, not certainty from one sample.
For Module 5, both technologies are mainly used to investigate:
Worked reading · match the claim to the technology
Step 1
Identify what information the technology produces.
Step 2
State whether it determines exact base order or compares marker patterns.
Step 3
Link the technology to inheritance patterns, relatedness or disease studies.
Step 4
Keep the conclusion matched to what the technology can really show.
Activities
Sort the Technology
For each statement below, decide whether it matches DNA sequencing or DNA profiling: a) determines the base order of a gene; b) compares selected marker patterns between samples; c) can identify a specific inherited base change directly.
Population Question
A researcher wants to compare whether a disease-linked variant is present in two populations. Explain why sequencing may be more useful than profiling for this question.
DNA sequencing
- Determines the exact order of nucleotide bases in a DNA sequence.
DNA profiling
- Compares patterns at selected DNA regions to distinguish or relate samples.
Main difference
- Sequencing reads base order directly, while profiling matches or compares marker patterns.
Biological importance
- Both technologies help investigate inheritance patterns in populations, including relatedness and inherited disease risk.
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ApplyBand 4(3 marks) 1. Define DNA sequencing and DNA profiling, and state one key difference between them.
AnalyseBand 5(4 marks) 2. Explain why DNA sequencing is useful for investigating inherited disease variants in a population.
AnalyseBand 5–6(5 marks) 3. A study uses DNA profiling to compare samples from several families in a population. Explain what kind of information profiling can provide, and one important limitation compared with DNA sequencing.
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Multiple choice
MC answers and full explanations are shown inline as you complete each question. Use the retry button to attempt a fresh set from the lesson bank.
Short Answer 1
DNA sequencing is the determination of the nucleotide base order in DNA. DNA profiling is the comparison of selected DNA marker patterns between samples. A key difference is that sequencing reads base order directly, while profiling usually compares patterns at selected regions rather than the full sequence.
Short Answer 2
DNA sequencing is useful because it identifies the exact nucleotide order and can reveal specific inherited variants or mutations associated with disease. This allows researchers to detect whether a disease-linked base change is present in individuals or populations and compare how common the variant is across groups.
Short Answer 3
DNA profiling can provide information about whether samples share similar selected DNA marker patterns, which can support inference about relatedness or inheritance links between individuals or families. A major limitation is that profiling does not usually give the full exact base order, so it cannot identify every specific variant in the same way that sequencing can.
Sequencing
Determines the exact order of nucleotide bases.
Profiling
Compares selected DNA marker patterns between samples.
Module 5 link
Both technologies support inference about inheritance patterns, relatedness and disease variants in populations.
Rapid-fire questions on DNA sequencing, DNA profiling and how each is used to study inheritance. Beat the boss to bank a tier — gold (perfect + fast), silver (80%+), or bronze (cleared).
Return to the claim from the start of the lesson and rewrite it using the correct distinction between sequencing and profiling.