Question

5. A eukaryotic protein-encoding gene contains two introns and three exons: exon 1–intron 1–exon 2–intron 2–exon 3. The 5ʹ splice site at the boundary between exon 2 and intron 2 has been eliminated by a small deletion in the gene. Describe how the pre-mRNA encoded by this mutant gene would be spliced. Indicate which introns and exons would be found in the mRNA after splicing occurs

Answer 1

In eukaryotes Introns and Exons are present on the genes.Introns are intervening sequences and do not code for proteins where as exons are expressed sequences that code for proteins.One or more Introns are removed during the translation process and the remaining exon sequences code for proteins.The removed exons are degraded rapidly by RNAses and the components are reused by the cell.

5'

Exon-1

Intron-1

EXon-2

Intron-2

Exon-3

deletion mutation at exon2 and intron2

5'

Exon-1

Intron-1

Exon-3