Question

The largest class of introns which are found in nuclear mRNA primary transcript is

• A. Spliceosomal introns
• B. Group II introns
• C. Group III introns
• D. Group V introns

Answer 1

Answer: (A)

Spliceosomal introns

Spliceosomal introns are characterized by specific intron sequences located at the boundaries between introns and exons. These sequences are recognized by spliceosomal RNA molecules when the splicing reactions are initiated in mRNA primary transcript. These introns are often much longer than their surrounding exons and they are the largest class of introns.

So, the correct option is 'Spliceosomal introns'.