what is splicing?why is it necessary in eukaryotes cells?
Splicing is a type of post transcriptional modification of the mRNA in eukaryotic cells. It is the process of removal of introns and joining of exons of the mRNA. It is necessary in eukaryotic cells because eukaryotic genes contain non coding regions (known as introns) in between coding regions (known as exons). So to make a functional protein from the mRNA, the introns must be removed and this is done by splicing.
In molecular biology and genetics, splicing is a modification of the nascent pre-mRNA taking place after or concurrently with its transcription, in which introns are removed and exons are joined. This is needed for the typical eukaryotic messenger RNA before it can be used to produce a correct protein through translation. For many eukaryotic introns, splicing is done in a series of reactions which are catalyzed by the spliceosome, a complex of small nuclear ribonucleoproteins (snRNPs), but there are also self-splicing introns (splicing takes place in the nucleus).