exon
/'eksɔn/
Học thuậtThân thiện
Definition
Noun: 1. A segment of a DNA or RNA molecule containing information coding for a protein or peptide sequence. In genes, exons are the coding regions that are expressed. They are interspersed with non-coding segments called introns, which are removed during RNA processing.
Usage
The word "exon" is a specialized scientific term used primarily in the fields of genetics, molecular biology, and biochemistry. It refers to the functional, protein-coding parts of a gene.
Examples
- Noun:
- The gene consists of four exons and three introns.
- Mutations within an exon can directly alter the structure of the resulting protein.
- During splicing, the introns are removed, and the exons are joined together to form messenger RNA (mRNA).
Advanced Usage
- Exon Skipping: A therapeutic approach where specific exons are omitted during RNA splicing, used to treat certain genetic disorders like Duchenne muscular dystrophy.
- The drug promotes exon skipping to restore the reading frame of the dystrophin gene.
- Exon Shuffling: A molecular mechanism for forming new genes, where exons from different genes are recombined.
- Exon shuffling is considered an important process in the evolution of protein diversity.
Variants and Related Words
- Exonic (adjective): Pertaining to or of the nature of an exon.
- They studied the exonic sequences for mutations.
- Exonization (noun): The evolutionary process by which a new exon is created from previously non-coding DNA.
- The paper described the exonization of an Alu element.
Synonyms
- Coding sequence (CDS): Refers to the portion of a gene's DNA or RNA that codes for protein. (Note: While highly overlapping, "exon" can sometimes include untranslated regions, whereas CDS is strictly the translated part.)
- Expressed sequence: A general term for parts of the genome that are transcribed.
Antonyms
- Intron (noun): A non-coding sequence of DNA that is interspersed between exons and is removed during RNA processing.
- Introns are spliced out, leaving only the exons in the mature mRNA.
Noun
- sequence of a gene's DNA that transcribes into protein structures
- exons are interspersed with introns