To find the base sequence of the DNA gene that originally produced the mRNA codon AGU, we need to consider the process of transcription, where DNA is transcribed to mRNA.
The mRNA codon AGU is transcribed from the DNA template strand. During transcription, the base pairs follow these rules:
- Adenine (A) pairs with Uracil (U) in RNA (however, in DNA it pairs with Thymine (T)),
- cytosine (C) pairs with guanine (G),
- guanine (G) pairs with cytosine (C),
- thymine (T) pairs with adenine (A).
Since the mRNA codon is AGU, the complementary DNA template strand would have the base sequence TCA (because A pairs with T, G pairs with C, and U in RNA corresponds to A in DNA).
Therefore, the base sequence of the DNA gene that originally produced this mRNA codon AGU is TCA.
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