Earlier in Maternal Effects and Cytoplasmic Inheritance
, we discussed induction of streptomycin resistant (sr
)and streptomycin dependent (sd
)mutants in Chlamydomonas.
Similar mutations are induced in bacteria in culture media. However, in the beginning these observations led some workers to believe that the medium selectively induced these adaptive
(or described as postadaptive
)mutations. However, with the help of several studies in bacteriophages conducted by S.E. Luria
and M. Delbruck
(Luria won Nobel Prize for medicine in the year 1975, with A.D. Hershey and R. Dulbecco), it could be demonstrated that the mutations were already present and that these adaptive mutations were only selected in culture medium (consult next main topic for more details). If these mutations were to be post-adaptive,
i.e. if these were selectively induced due to culture medium, this concept will be aLamarckian
concept and we may have to accept inheritance of acquired characters.