Introns in Biological Definition

Gene

... internally by non-coding sequences called introns , which can be many times longer than the genes themselves. introns are removed on the heels of transcription by ... a gene, by keeping the exons and removing the introns . So, the DNA strand needs to be in an exon to ...

Intron

... introns are sections of DNA within a gene that do ... before it is exported from the cell nucleus . introns exist mainly (but not only) in eukaryotic ... remain in the spliced mRNA are called exons . introns sometimes allow for alternative splicing of a ...

Splicing (genetics)

... known as exons (expressed codons) and introns (interrupting codons). In contrast to ... called pre-mRNA that is composed of both introns and exons (see transcription ). Pre-mRNA has to ... be translated into protein. During splicing, the introns are removed from the mRNA using one of three ...

Alternative splicing

... the pre-mRNA has been transcribed from the DNA , it includes several introns and exons . In nematodes , the mean is 4-5 exons and introns; in the fruit fly Drosophila there are more than 100 introns and exons in one transcribed pre-mRNA. But what is an intron and what is ...

Spliceosome

... complex of RNA and many protein subunits, that remove the non-coding introns from unprocessed mRNA . The mRNA of prokaryotes is simpler, and they ... splicing Alternative splicing (the re-combination of different introns ) is a major source of genetic diversity in eukaryotes. For example ...

Enhancer

... some have been found to bind several hundreds of thousands base pairs upstream or downstream of the start site. Enhancers can also be found inside introns . An enhancer's orientation may even be reversed without affecting its function. Furthermore, an enhancer may be excised and inserted elsewhere in ...