Question

The given nucleotide sequence is found in a short stretch of DNA. 5′–GA–3′ 3′–CT–5′ What mutant sequence can result from spontaneous depurination in this stretch of DNA? 5′–GT–3′ 3′–CA–5′ 5′–CA–3′ 3′–GT–5′ 5′–AA–3′ 3′–TT–5′ 5′–GC–3′ 3′–CG–5′ 5′–GG–3′ 3′–CC–5′ What mutant sequence can result from spontaneous deamination in this stretch of DNA?

Answer 1

Depurination:

5′– –3′ 5′– T–3′ 5′–C –3′ 5′– –3′ 5′– C–3′ 5′– –3′

3′–CT–5′ 3′–C –5′ 3′– T–5′ 3′–TT–5′ 3′–C –5′ 3′–CC–5′

Deamination:

5′–GA–3′ 5′–GT–3′ 5′–UA–3′ 5′–AA–3′ 5′–GU–3′ 5′–GG–3′

3′–UT–5′ 3′–UA–5′ 3′–GT–5′ 3′–TT–5′ 3′–UG–5′ 3′–UU–5′

Step-by-step explanation:

DNA is very stable molecule but mutations may occurs in this stable molecules. Any change in DNA sequence either by mistakes are environmental factors like UV light is known as Mutation.

Major mutation occurs because of heat fluctuations. These mutations include depurination and deamination.

Depurination:

It is the process of removing adenine and guanine collectively called as Purines from DNA. About 5000 purine bases are removed every day human DNA.

Deamination:

It is the process of removal of amino group from Cytosine. This result in formation of uracil in DNA. This conversion of Cytosine to Uracil occurs at a rate of about 100 bases per cell per day.

Answer of the question:

Sequence:

5′–GA–3′ 5′–GT–3′ 5′–CA–3′ 5′–AA–3′ 5′–GC–3′ 5′–GG–3′

3′–CT–5′ 3′–CA–5′ 3′–GT–5′ 3′–TT–5′ 3′–CG–5′ 3′–CC–5′

Depurination:

5′– –3′ 5′– T–3′ 5′–C –3′ 5′– –3′ 5′– C–3′ 5′– –3′

3′–CT–5′ 3′–C –5′ 3′– T–5′ 3′–TT–5′ 3′–C –5′ 3′–CC–5′

Deamination:

5′–GA–3′ 5′–GT–3′ 5′–UA–3′ 5′–AA–3′ 5′–GU–3′ 5′–GG–3′

3′–UT–5′ 3′–UA–5′ 3′–GT–5′ 3′–TT–5′ 3′–UG–5′ 3′–UU–5′