Mid-blastula transition (MBT) in amphibians is characterized by which of the following events?
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Correct answer: The onset of zygotic transcription
During early cleavage, development is driven exclusively by stored maternal mRNA. At the mid-blastula transition, the cell cycle lengthens, and the embryo's own genome is transcribed for the first time, shifting developmental control from maternal to zygotic factors.
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