Concept
Gene expression
Gene expression is the controlled production of RNA and protein from DNA, including when, where, and how much a gene is used.
Expression control is the cell’s first answer to environment and development — a core undergrad mechanism.
Evidence
What the evidence shows
Drawn from 13 studies in this library. Each claim links to the studies behind it.
Multiple empirical papers in this library examine gene expression with mechanistic biological findings.
PC5 separates DE cells; metabolism genes load on that axis; severe hypoxia (1.5% O2) increases CXCR4+ DE-like cells versus higher O2.
ESE disruption and near-splice positions show signatures consistent with purifying selection; splicing constrains human exon evolution.
Noise is minimized for essential genes and complex subunits via transcriptional/translational control, at a cost; noise appears generally deleterious.
FECR1 is a FLI1 exonic circRNA that activates FLI1 epigenetically and promotes invasive phenotypes; FLI1 is elevated in tumor vs adjacent tissue.
Open questions
Where studies disagree
Open questions, not settled findings — worth knowing before you cite any one of these.
Systems and scales differ across gene expression studies (species, tissues, methods), so mechanisms should not be over-generalised.
Common misconceptions
Gene expression findings from one model organism always transfer to humans.
Model systems teach mechanism; transfer to other species is a separate empirical claim.
Exam-style questions
Short-answer questions that ask you to explain or compare, not recall.
What is Gene expression?
Gene expression is the controlled production of RNA and protein from DNA, including when, where, and how much a gene is used.
Why does Gene expression matter for biology undergraduates?
Expression control is the cell’s first answer to environment and development — a core undergrad mechanism.
The studies
- How do microRNAs recognize their targets?
Sites with as little as seven base pairs matching the miRNA 5′ end can confer regulation; such 5′-dominant sites are common in conserved 3′ UTRs.
- Why do identical cells make different amounts of mRNA?
Mammalian genes switch rarely between ON and OFF, so intrinsically random transcriptional bursts create large cell-to-cell mRNA differences.
- Cataloging mammalian circular RNAs
Thousands of mammalian circRNAs arise by back-splicing and can be quantified across ENCODE cell types.
- MYB transcription-factor families in plants
Rice and Arabidopsis encode large MYB families dominated by R2R3 types with distinct expression patterns.
- What marks definitive endoderm progenitors in hESCs?
Single-cell RNA-seq separates definitive endoderm progenitors and links metabolism/hypoxia to DE differentiation.
- FLI1 circRNA FECR1 drives metastasis
Exonic circular RNA FECR1 binds the FLI1 promoter and epigenetically activates FLI1 in breast cancer.
- Where does cells minimize expression noise?
Yeast minimizes protein-expression noise preferentially for essential genes and protein-complex subunits, supporting that noise is generally harmful.
- Do SNPs prove exonic splicing enhancers are real?
Human polymorphism patterns validate computationally predicted ESEs and show splicing constrains exon evolution.
- Multi-tissue networks behind obesity biology
Adipose–hypothalamus coexpression subnetworks, including circadian genes, associate with obesity-related biology beyond single-tissue views.
- Pea aphid miRNAs and plasticity
Pea aphids encode dozens of miRNAs whose expression tracks phenotypic plasticity.
- Atlantic cod heat-shock gene responses
Heat shock elevates cortisol and rewires chaperone and stress-gene expression in Atlantic cod tissues.
- How does fish liver gene expression change under confinement stress?
Microarrays track the time course of gilthead sea bream liver transcriptional responses after confinement stress linked to cortisol biology.
- What do co-fermenting yeasts express together?
In balanced continuous co-culture, L. thermotolerans contributes ~24% of anaerobic reads vs ~8% aerobically.
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Flashcards
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