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Virus assembly


Conditional lethals
Sydney Brenner Scientist
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There'd been a lot of work done on conditional lethals of bacteriophage, in that people had started to identify temperature-sensitive mutants. And later on the amber mutants were identified as conditional lethals… finding all the genes of an organism. While we were working in this I had started to isolate a number of mutants in bacteriophage T4 called minutes. I worked extensively on these minutes during 1960 when I could show that there were lots and lots of different ones. And they were difficult to work with, but we did in fact map quite a large number of ones. I didn't have the sense to see that these were just leaky mutants – that is, almost conditional, almost lethals. And that had I incubated some of them at a lower temperature I would have discovered that quite a lot of them were temperature-sensitive, and I just hadn't gone up high enough to knock them out completely. Later we did check our minute collection for temperature sensitivity and found indeed that they were temperature-sensitives. But that whole concept of conditional lethals opened up genetics in a most remarkable way. And in fact became the basis for a considerable amount of genetics since that time, and gave rise I think to the concept, which became important later, that Seymour used to call genetic dissection. The… the DNA mutants were of course a paradigm for me. No doubt other people will have their own examples. But that showed exactly what you had to accomplish in any large-scale genetic experiment, which was roughly speaking; isolate as many mutants as you can, classify them by complementation, so that you've got all the ones in the same gene, and then study them as deeply as you can in order to find out what they do. And that has… has flowed through all my work since the early '60s – just that general approach.

South African Sydney Brenner (1927-2019) was awarded the Nobel Prize in Physiology or Medicine in 2002. His joint discovery of messenger RNA, and, in more recent years, his development of gene cloning, sequencing and manipulation techniques along with his work for the Human Genome Project have led to his standing as a pioneer in the field of genetics and molecular biology.

Listeners: Lewis Wolpert

Lewis Wolpert is Professor of Biology as Applied to Medicine in the Department of Anatomy and Developmental Biology of University College, London. His research interests are in the mechanisms involved in the development of the embryo. He was originally trained as a civil engineer in South Africa but changed to research in cell biology at King's College, London in 1955. He was made a Fellow of the Royal Society in 1980 and awarded the CBE in 1990. He was made a Fellow of the Royal Society of Literature in 1999. He has presented science on both radio and TV and for five years was Chairman of the Committee for the Public Understanding of Science.



Listen to Lewis Wolpert at Web of Stories



Tags: 1960, Seymour Benzer

Duration: 2 minutes, 56 seconds

Date story recorded: April-May 1994

Date story went live: 24 January 2008