DNA, Genes, and Gene Expression
From DNA to Trait
Central dogma
Genetic information is typically stored in DNA, transcribed into RNA, and translated into protein. Changes at any step can alter phenotype, so engineered DNA often targets transcription, translation, or protein activity.
Important components
Levels of control
DNA level
- Edit a gene or regulatory element
- Can have long-lasting effects
RNA level
- Change mRNA abundance or stability
- Effects are often more transient
Which sequence is most directly responsible for the amino acid sequence of a protein?
The coding sequence contains codons that determine amino acids.
Correct answer: Coding sequence
What is the main difference between an exon and an intron?
Splicing removes introns and joins exons to form mature mRNA.
Correct answer: Exons remain in mature mRNA, while introns are removed during splicing
An enhancer usually affects which process?
Enhancers increase transcriptional output by helping recruit regulatory proteins.
Correct answer: Transcription
Concept check
A mutation is not automatically harmful. In engineering, the key question is whether a sequence change creates the intended molecular effect.
How a gene becomes a trait
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1
Step 1: DNA contains a gene and its regulatory regions.
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2
Step 2: Transcription produces RNA.
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3
Step 3: RNA processing creates mature mRNA.
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4
Step 4: Translation produces a protein.
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5
Step 5: Protein activity contributes to phenotype.