Published online by Cambridge University Press: 14 April 2009
We have isolated a number of λ dg HFT lysates which carry proximal fragments of the galactose operon. Most of these have been shown to be different, and each terminates in either the kinase or transferase cistron. They divide the kinase cistron genetically into seven blocks of mutants, and the transferase into eight.
When a λ dg is used to transduce a bacterium which carries a mutation in a cistron which is intact in the λ dg the transduction frequency is high in the presence of λ-helper. This is attributed to integration of the transducing fragment at the λ-attachment site and complementation between the two operons in the heterogenote. When the same λ dg transduces a mutation lying in the cistron in which the λ dg terminates, so that recombination within the galactose operon is obligatory, the transduction frequency is 10 to 1000 times less.
In such cases there is a general increase in transduction frequency between distal mutations (i.e. those lying near the termination of the deletion) and proximal mutations, but the relationship does not hold for many individual pairs of mutants, probably due to physiological differences between the bacterial strains.
To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Dropbox account. Find out more about saving content to Dropbox.
To save this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Google Drive account. Find out more about saving content to Google Drive.