In an experiment, researchers split a bacterial colony in two, allowing each of the new colonies to evolve separately.They then sequence a gene from colony 1 and colony 2.In the common ancestor, at nucleotide site 167 there is T.In colony 1, there is C; in colony 2, there is T.This is an example of a _______ substitution.

Question

Quizplus · Accepted Answer

A single substitution has occurred because only one nucleotide has changed (from T in the ancestor to C in colony 1 or remaining as T in colony 2). Coincident substitution occurs when two or more nucleotides change at the same time, while parallel substitutions occur independently in different lineages. Back substitutions are rare and involve the reversal of a previously occurred substitution. Multiple substitutions occur when two or more substitutions occur at the same nucleotide site.

In an Experiment, Researchers Split a Bacterial Colony in Two