A species of insect that lives solely on pine sap was found to contain a bacterial symbiont. Genome sequencing of both the host and the symbiont revealed that the symbiont lacked many genes required for energy production, and the host lacked genes for biosynthesis of several essential amino acids. What is/are the most likely mechanism(s) that caused the loss of these genes?
A) coevolution
B) horizontal gene transfer
C) increased mutation rate
D) horizontal gene transfer and increased mutation rate

Question

Quizplus · Accepted Answer

Coevolution between the host and the symbiont likely led to the loss of genes in both organisms, as each relied on the other to provide essential functions, making certain genes redundant and thus more susceptible to loss over evolutionary time.

A Species of Insect That Lives Solely on Pine Sap