A sample of DNA containing the wild type sequence is treated with hydroxylamine. 5'-ATGT-3' 3'-TACA-5' Select the mutant sequence that is most likely to be observed after two rounds of replication. O 5'-GTGT-3' 3'-CACA-5' O 5'-ATGT-3' 3'-TACA-5' O 5'-ATTT-3' 3'-TAAA-5' O 5'-AAGT-3' 3'-TTCA-5' O 5'-ATAT-3' 3'-TATA-5'
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Hydroxylamine (NH2OH) is a mutagen that specifically reacts with cytosine (C). It modifies cytosine to a derivative that can base-pair with adenine (A) instead of guanine (G). This leads to C to T transitions (or G to A transitions on the complementary strand) Show more…
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The following nucleotide sequence is found in a short stretch of DNA: $$\begin{aligned}&5^{\prime}-\text {ATGT}-3^{\prime}\\&3^{\prime}-\text {TACA}-5^{\prime}\end{aligned}$$ If this sequence is treated with hydroxylamine, what sequences will result after replication?
The following nucleotide sequence is found in a short stretch of DNA: $$\begin{aligned} &5^{\prime}-A T G T-3^{\prime}\\ &3^{\prime}-\text { TACA-5' } \end{aligned}$$ If this sequence is treated with hydroxylamine, what sequences will result after replication?
The URA3 gene is required to make uracil in yeast. A geneticist obtained a yeast strain from another lab for an experiment and discovered it is auxotrophic for uracil due to a mutation in the ura3 gene. She sequenced the URA3 and ura3 alleles and discovered a single base pair substitution in the ura3 allele (shown below). URA3: 5' . . . AATGATGGA . . . 3' 3' . . . TTACTACCT . . . 5' ura3: 5' . . . AATGCTGGA . . . 3' 3' . . . TTACGACCT . . . 5' To use the strain, she needs it to be prototrophic for uracil so she decided to revert the ura3 allele back to URA3. To increase the frequency of reversion, she treated the ura3 cells with a mutagen, and then plated the mutagenized cells onto medium lacking uracil to select for colonies that could grow. Assume that only one base pair substitution occurs in each revertant. The mutagens she had on hand were: Type of mutagen | Mode of action hydroxylamine | Modifies C so that it pairs with A X-rays | Makes double strand breaks Nitrous acid | Modifies A so that it pairs with C Oxidizer | Modifies G so that it pairs with A Based on this information select the statements below that are TRUE. A. The mutation in ura3 is a transition base substitution. B. The mutagen MOST LIKELY to revert the ura3 mutant to URA3 is the oxidizer. C. The mutagen MOST LIKELY to revert the ura3 mutant to URA3 is hydroxylamine. D. The mutagen MOST LIKELY to revert the ura3 mutant to URA3 is nitrous acid. E. The mutation in ura3 is a transversion base substitution. F. The mutagen MOST LIKELY to revert the ura3 mutant to URA3 are X-rays.
Madhur L.
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