Volume 3

Gene expression / Benjamin Lewin.

  • Lewin, Benjamin.
Date:
1974-1977
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Gene expression / Benjamin Lewin. Source: Wellcome Collection.

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    molecular events experimental observations S // fragments of duplex DNA added to competent cell \ -\- ' transforming DNA binds to recipient cell single transforming strand enters cell; other strand is degraded DNA becomes resistant first to washing and then to DNAase DNA enters eclipse phase and is recovered in single strand form recipient chromosome unwinds and initiates pairing with donor strand pairing continues until donor strand is inserted into genome gaps are closed and eclipse phase ends and donor donor strand covalently DNA is recovered in duplex integrated into form as hybrid with recipient genome recipient Figure 1.3: model for transformation of pneumococcus. The steps through which transform ing DNA passes are shown but their sequence is not entirely established; for example, it is not clear whether one strand of the transforming DNA is degraded during or following entry into the cell. Phenotypic expression of a donor marker takes place only after the final stage shown here of covalent integration into the recipient genome.