Imagine a human protein containing 33 repeats of a simple domain arranged in tandem. In contrast, a homolog found in bacteria contains only one domain. What is the minimum number of duplication events that can account for the evolution of this protein since our divergence from bacteria? Write down the number as your answer, e.g. 200.

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Quizplus · Accepted Answer

Duplication of DNA segments has been a widespread evolutionary event that can happen over long or short blocks of the genome. It can exponentially expand the block to create tandem repeated arrays. For example, in an ideal case, only five duplications are needed to create 32 (that is, 2⁵) repeats of an original DNA segment that encodes a protein domain. One more is needed to make the total 33 repeats. In reality, however, more than six duplication events might have been involved.

Imagine a Human Protein Containing 33 Repeats of a Simple