Why Do Exons Remain?

Introns and exons are nucleotide sequences within a gene. Introns are removed by RNA splicing as RNA matures, meaning that they are not expressed in the final messenger RNA (mRNA) product, while exons go on to be covalently bonded to one another in order to create mature mRNA.

Do exons remain?

Exons are coding sections of an RNA transcript, or the DNA encoding it, that are translated into protein. ... These pre-mRNA molecules go through a modification process in the nucleus called splicing during which the noncoding introns are cut out and only the coding exons remain.

Why are exons conserved?

It is widely accepted that within genomes, protein-coding exons are naturally more conserved over introns due to natural selection. ... “We demonstrate for the first time that exons hold fewer mutations than other regions because these regions are repaired more effectively.”