Chlamydomonas, a unicellular green algae, is sensitive to an antibiotic, erythromycin. If mt- mating- type alga that is sensitive is mated with an mt+ cell that is resistant, and if the mt+ strain donates chloroplasts, what results do you expect and why?
A) All progeny are resistant because cpDNA is responsible for the resistant phenotype.
B) Approximately half the progeny are sensitive because cpDNA is responsible.
C) Approximately half the progeny are sensitive because this is the recessive trait.
D) All progeny are sensitive because sensitivity is the dominant trait.
E) All the progeny are sensitive because this is the recessive trait.

Question

Quizplus · Accepted Answer

Chloroplast DNA (cpDNA) in Chlamydomonas can carry genes responsible for antibiotic resistance, such as erythromycin resistance. If the mt+ strain, which is resistant, donates chloroplasts to the progeny, all of them would inherit this resistance, assuming that the resistance trait is encoded in the chloroplast DNA and not affected by nuclear DNA.

Chlamydomonas, a Unicellular Green Algae, Is Sensitive to an Antibiotic