Select all that applyDifficulty 3/5 · ChallengingOlympiadArgumentationRepresenting data
Liver and neurons: same genes, different messages
Researchers took liver cells and brain neurons from the same adult mouse. From each sample they extracted genomic DNA and mRNA, then used labelled probes to detect three genes: albumin (a blood protein made by the liver), neurofilament light chain (a structural protein of neurons) and β-actin (a cytoskeleton protein used by all cells). DNA was cut with a restriction enzyme and probed on Southern blots, and mRNA was probed on Northern blots, loading equal amounts from each tissue.
Experimental setup
- Question
- Do liver cells and neurons differ in the genes they carry, or in the genes they express?
- Independent variable
- Cell type (liver or neuron)
- Dependent variable
- Probe signal for each gene in genomic DNA and in mRNA
- Kept constant
- Same mouse · Equal amounts of DNA or RNA loaded · Same probes and exposure
- Groups
- Liver: Genomic DNA and mRNA from hepatocytes
- Neurons: Genomic DNA and mRNA from brain neurons
Data
| Gene probed | Liver DNA | Neuron DNA | Liver mRNA | Neuron mRNA |
|---|---|---|---|---|
| Albumin | One band, 6.1 kb | One band, 6.1 kb | 95 | nd |
| Neurofilament light chain | One band, 4.3 kb | One band, 4.3 kb | nd | 88 |
| β-actin | One band, 3.4 kb | One band, 3.4 kb | 72 | 70 |
Which conclusions do these data support? Select all that apply.
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