Final answer:
Splice sites in pre-mRNA are read in pairs, where snRNPs binding to 5' and 3' splice sites within the spliceosome leads to precise removal of introns and joining of exons. Mutations in these sites or spliceosomal components can cause mis-splicing and genetic disorders.
Step-by-step explanation:
Splice sites are critical regions in pre-mRNA that dictate where splicing will occur to remove introns and join exons together, forming a mature mRNA molecule. These sites are read in pairs: the 5' splice site at the beginning of an intron and the 3' splice site at the end. snRNPs (small nuclear ribonucleoproteins) bind to these sites and draw them close together within the spliceosome, a complex responsible for catalyzing the splicing reaction. Here, the intron forms a loop or 'lariat' structure, which is then excised, allowing the exons to be ligated together. This splicing mechanism ensures that the resulting mRNA is composed only of sequences that will code for proteins.
Mutations in the splice sites or spliceosomal components can result in incorrect splicing, potentially leading to various genetic disorders due to the disruption of normal protein synthesis. Since splicing is a precise process, it must read the splice sites in pairs to ensure accurate removal of introns and joining of exons, crucial for creating functional mRNA.