Question

A patient wants to know if he is heterozygous for a rare allele that could predispose him to cancer. The gene concerned contains the sequence, 5-prime GACAGTTCCCGTATTCTTG 3-prime. Using an appropriate PCR primer, this sequence (including adjacent 5-prime and 3-prime regions) was amplified from a sample of the patients DNA. Unfortunately, the lab technician forgot to label which lane contained which dideoxynucleotide when he ran the gel.

Which lane corrresponds to which dideoxynucleotide? Answer with A for dideoxyadenine, C for dideoxycytosine, G for dideoxyguanine, and T for dideoxythymine. List the lanes in order from left to right, e.g. ACGT.

Is the man heterozygous for the rare allele and, if so, what nucleotide substitution has occurred to convert the normal allele into the mutant allele? Answer yes or no followed by the original base and the mutated base, N N if no change seen here, e.g. yes A T or no N N. Note the space between each component.

What amino acid sequence does the mutant allele have in this region of the protein if the normal amino acid sequence is gln-phe-pro-tyr-ser? For your answer, follow this model using the standard 3-letter amino acid identifiers.

Answer 1

According to the given information, the lane 1 indicates C followed by T, A, and G from left.

$9k=$

In the given sequence, C is followed by C, while in the gel the C is followed by T.

Thus, it indicates base substitution (transition) where cytosine is replaced with thymine in the individual.

$9k=$

According to the above picture, the base substitution has replaced proline with leucine in the mutated sequence.