intron
C1+ (Specialized)Formal, Technical (Molecular Biology/Genetics)
Definition
Meaning
A non-coding sequence of DNA within a gene that is removed during RNA splicing.
Any intervening, non-expressed sequence of genetic material.
Linguistics
Semantic Notes
The term was coined as a portmanteau of 'intragenic region' or 'intervening sequence'. It contrasts directly with 'exon', the coding sequence that remains in mature mRNA.
Dialectal Variation
British vs American Usage
Differences
No significant lexical or semantic differences. Both dialects use the term identically in technical contexts.
Connotations
Solely technical, with no colloquial connotations in either dialect.
Frequency
Used with identical frequency in professional/academic contexts in both regions. Virtually absent from general discourse.
Vocabulary
Collocations
Grammar
Valency Patterns
The [GENE] contains [NUMBER] introns.Splicing removes the intron.A mutation within the intron.Vocabulary
Synonyms
Strong
Neutral
Vocabulary
Antonyms
Usage
Context Usage
Business
Not used.
Academic
Core term in genetics and molecular biology research papers and textbooks.
Everyday
Extremely rare; only in popular science contexts.
Technical
Essential, high-frequency term in laboratory protocols, bioinformatics, and genetic engineering.
Examples
By Part of Speech
adjective
British English
- The intronic sequence was highly variable.
- Intron retention can regulate gene expression.
American English
- An intronic mutation disrupted the splice site.
- They studied intronic enhancer elements.
Examples
By CEFR Level
- Genes are not continuous; they contain sections called introns that are removed.
- The researchers identified a new intron in the plant's DNA.
- During RNA splicing, the spliceosome catalyses the precise removal of each intron and ligation of the exons.
- Evolutionary analysis suggests this group II intron was acquired via horizontal gene transfer.
- Mutations in intron splice sites can lead to serious genetic disorders.
Learning
Memory Aids
Mnemonic
Think: INTRuder ON the gene line. An intron is a sequence that intrudes into the gene code and must be taken 'on' its way out during splicing.
Conceptual Metaphor
The genome as edited text: Introns are the rough drafts or the notes in the margin that are cut out to create the final, readable version (the exon).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid translating as 'интрон' in non-scientific contexts where the term is unknown. The concept may be described as 'некодирующий участок гена'.
Common Mistakes
- Confusing 'intron' with 'exon'.
- Pronouncing it as /aɪnˈtrɒn/ (like 'intro' with an 'n').
- Using it as a general term for any non-functional DNA.
Practice
Quiz
What is the primary functional relationship between an intron and an exon?
FAQ
Frequently Asked Questions
An intron is a non-coding sequence that is removed during RNA processing, while an exon is a coding sequence that is expressed in the final mature RNA.
Yes, once considered 'junk DNA', many introns are now known to contain regulatory elements, such as enhancers, or can produce non-coding RNAs. They also contribute to genetic diversity through alternative splicing.
Yes. Mutations in intronic sequences, especially those near splice sites, can disrupt normal RNA splicing, leading to the production of faulty proteins and resulting in genetic diseases.
No. They are common in eukaryotic genomes but are extremely rare in most prokaryotes (bacteria and archaea).