A crucial photosynthetic gene of the cyanobacterium that gave rise to the cyanelle is called psaE. This gene is present in the nuclear genome of the cercozoan, but is not in the genome of the cyanelle. This is evidence of
A) reciprocal mutations in the cyanelle and nuclear genomes.
B) horizontal gene transfer from bacterium to eukaryotes.
C) genetic recombination involving a protist and an archaean.
D) the origin of photosynthesis in protists.
E) transduction by a phage that infects both prokaryotes and eukaryotes.

Question

Quizplus · Accepted Answer

The presence of the psaE gene in the nuclear genome of the cercozoan, but not in the genome of the cyanelle, suggests that this gene was horizontally transferred from a cyanobacterium to the cercozoan ancestor. Horizontal gene transfer is the movement of genetic material between different organisms that are not in a parent-offspring relationship, and it is a common mechanism of gene acquisition in prokaryotes and some unicellular eukaryotes.

A Crucial Photosynthetic Gene of the Cyanobacterium That Gave Rise