What process involves the removal of intron sequences and joining of exons?

The process involving the removal of intron sequences and the joining of exons is known as splicing. In eukaryotic cells, genes are initially transcribed into precursor messenger RNA (pre-mRNA), which contains both exons (coding regions) and introns (non-coding regions). During RNA processing, the introns are excised from the pre-mRNA, and the exons are ligated together to form a mature messenger RNA (mRNA) strand. This spliced mRNA is then transported out of the nucleus and translated into a protein.

Splicing is crucial for gene expression, as it ensures that only the coding regions are included in the mRNA that will be translated into proteins. This process also allows for alternative splicing, where different combinations of exons can be joined together, leading to the production of multiple protein variants from a single gene.