Below is a schematic diagram of gene Y which encodes protein

Below is a schematic diagram of gene Y which encodes protein Y and Y\' (cleverly enough). The promoter region is indicated by the yellow box and the direction of transcription is shown. The numbers correspond to nucleotide positions within the gene. The sequences between 1-100 is the 5\' UTR and positions 5100-5500 is the 3\' UTR (neither is removed by splicing). Polyadenylation is indicated with an A. Draw the primary transcript. How long is it (in nucleotides)? Two different mature transcripts are produced from this gene. One is approximately 2800 nucleotides long and encodes protein Y and the other is 3800 nucleotides long and produced protein Y\'. Draw these mature transcripts. The following mutations occurred in gene Y. Draw the mature transcripts that would be produced and indicate what effect this would have on the production of proteins Y and Y\': The base pair at position 200 was changed from an A/T to a G/C. The base pair at position 3799 was change from a G/C to an

Solution

Answer to c>

(i) Due to a transition mutation at position 200, which a start codon (most commonly AUG) it will lead to failed translation. Hence there will be no protein product, either Y or Y\'.

(ii) Again due to a transition mutation (i.e. from C <-> T) at the first nucleotide of the base pair position 1267 (3799/3) there could be missense mutation that gets translated into a different amino acid. This mutation will affect the functional role of Y\'.

(iii) This is an example of transversion mutation (G <-> T) at the last nucleotide of base pair position 1101 which could affect protein structure and function of Y.