I have been given a DNA nucleotide sequence and have established the equivalent mRNA sequence.I have then been given 2 mutations and I have worked out the new mRNA sequence but I have to suggest why it may change the function of the new protein. The new sequence is AUA AGC UUU, and I know that the start codon is always AUG, but I'm not sure how it would change the function of the protein? Any help would be appreciated!

Question

I thnk the answer would be that this mRNA would not be translated into a polypeptide chain?

Further on in the question it states that the mutation found is the change to produce the dominant gene for continued lacatse production throughout adult life. However, if AUG is always the start codon, the how would the new sequence be possible? If it's not translated into a polypeptide chain then what is it? I think I have missed something vital here!

I've come up with: Ile,Ser, Phe. Can this be done? if so how does it change the function of the protein?

I got the same. It says in bk 9 that a mutation in the DNA code can be transcribed into mRNA and subsequently translated into a protein on p130. It's also got some info on p127. I'm not too sure why it may change the function. I'm guessing the code is right, but if it's not a polypeptide chain then I don't know what it is! Great way to spend the easter holidays.