Answer: Genes contain exons which are coding and introns which are non coding sequences. Introns are interspersed between exons. Gene expression results in transcription of mRNA. A mature mRNA is formed by splicing of the introns and stitching exons together. This stitching can vary, If the cell stitches the exons together in one way, it makes one kind of mRNA. If it stitches the exons together in another way, it makes a different mRNA. As a result, a single gene can actually produce many different mRNA. Solution Answer: Genes contain exons which are coding and introns which are non coding sequences. Introns are interspersed between exons. Gene expression results in transcription of mRNA. A mature mRNA is formed by splicing of the introns and stitching exons together. This stitching can vary, If the cell stitches the exons together in one way, it makes one kind of mRNA. If it stitches the exons together in another way, it makes a different mRNA. As a result, a single gene can actually produce many different mRNA..