One form of cystic fibrosis is caused by a mutation in the m

One form of cystic fibrosis is caused by a mutation in the middle of the DNA sequence of the CFTR gene. If you look at the protein produced from this mutated sequence, and the protein is the normal length, what type of mutation is most likely? Frame shift Silent Missense Nonsense Either answer B or C could be true. In the following sequence of DNA the underline base has been mutated. What type of mutation is this? 5\' - G A T C T C C G A A T T-3\' original strand 5\' - G A T C TC C C A A T T - 3\' mutated strand Transition Transversion Neither Insertion Deletion Spontaneous mutations include Depurination, deamination, errors in DNA replication UV light, radiation, deamination, depurination UV light, radiation, deamination, errors in replication UV light, errors in DNA replication, deamination, depurination Two teenage boys meet at a clinic set up to treat muscular dystrophy. The boy who is more severely affected has a two-base insertion at the start of his dystrophin gene. The other boy has the same two-base insertion but also a third base inserted a few bases away. Explain why the second boy\'s illness is milder.

Solution

Explanation: As the chain length remain normal so it can`t be frame shift.

If the mutation is silent then no effect should be observed. But here disease occurs.

If the mutation is nonsense then also the chain length should be shortened due to stop codon formation.

Explanation: When a Purine is substituted by a Pyrimidine then it is called transversion. Here G is Purine and C is Pyrimidine.

Explanation: UV light and Radiation causes serious damages in the DNA which cannot be repaired easily. So, these mutations are not spontaneous. But Depurination, Deamination, Errors in DNA replication are such type of mutations which can be repaired by cellular mechanism.

But if a third base inserted after a few bases away then DNA sequence between the two bases insertion site and single base insertion site get modified. After that rest of all amino acids become normal. So, illness is milder for the second boy.

1. C) Missense mutation

Explanation: As the chain length remain normal so it can`t be frame shift.

If the mutation is silent then no effect should be observed. But here disease occurs.

If the mutation is nonsense then also the chain length should be shortened due to stop codon formation.

2. B) Transversion

Explanation: When a Purine is substituted by a Pyrimidine then it is called transversion. Here G is Purine and C is Pyrimidine.

3. A) Depurination, Deamination, Errors in DNA replication

Explanation: UV light and Radiation causes serious damages in the DNA which cannot be repaired easily. So, these mutations are not spontaneous. But Depurination, Deamination, Errors in DNA replication are such type of mutations which can be repaired by cellular mechanism.

4.Genetic code is formed by 3 nucleotides bases. It means every 3 non-overlapping nucleotides code a particular amino acid. So, if two nucleotides base inserted in DNA sequence then the rest of all nucleotides in the DNA sequence get modified. It means from the two bases insertion site all the amino acid sequence changed. So, it is severe condition for the first boy.

But if a third base inserted after a few bases away then DNA sequence between the two bases insertion site and single base insertion site get modified. After that rest of all amino acids become normal. So, illness is milder for the second boy.