question: What is the term that describes the way the endosymbiont ca n't go back to its original phenotype ?
answer: Muller 's ratchet phenomenon
turker_answer: Muller 's ratchet phenomenon is the term that describes the way the endosymbiont ca n't go back to its original phenotype .
rule-based: The term that describes the way the endosymbiont ca n't go back to its original phenotype is Muller 's ratchet phenomenon .