Available online
Description
The programme looks at how twentieth century geneticists have attempted to answer the question 'What is a gene?'
The programme looks at how twentieth century geneticists have attempted to answer the question 'What is a gene?'
| Module code and title: | S299, Genetics |
|---|---|
| Item code: | S299; 05 |
| First transmission date: | 12-04-1976 |
| Published: | 1976 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:24:30 |
| + Show more... | |
| Producer: | Roger Jones |
| Contributor: | Neville Symonds |
| Publisher: | BBC Open University |
| Keyword(s): | Beadle; Tatum; DNA; Double-helical structure; Garrod; Genes; Heritable diseases; One gene - one enzyme; Structure and function; T4 virus |
| Footage description: | Neville Symonds introduces the programme with a short discussion of the impact, on genetics, of Schroedinger's book "What is life?". Symonds explains how the concept of genes originated. He uses models and micrographs to show how these ideas have changed. Symonds discusses historical changes of thinking on the ways in which genes make up the genotype of individuals. He summarises the work of Garrod, of Beadle and Tatum (the one gene, one enzyme theory) and of Watson and Crick. Symonds, with a model of a T4 phage, discusses the uses of phage to answer questions about genes. He explains the advantages of using phage as experimental organisms and then goes on to demonstrate some of the apparatus for doing phage experiments. Symonds demonstrates aspects of those experiments concerned with numbers of phage and bacteria. Symonds, with several micrographs of phage and bacteria, discusses the life cycle of the T4 phage. He points out how phage DNA recombination can occur during multiple infection of a bacterium. Symonds explains how a phage cross can be induced. He explains how mutants are used to detect results of phage recombinations. Symonds uses several graphic aids to help explain the results of rll mutant experiments. Symonds goes on to discuss the way in which the methods pioneered by Benzer can be used to examine the fine structure of genes to answer such questions as gene size in terms of nucleotide pairs and how closely two independent r mutations can be found which are still separable by genetic re-combination. Symonds uses several graphic aids, micrographs of experimental results to explain techniques used by Benzer to get his results. Symonds gives the results of Benzer's work, the size of a gene in terms of nucleotide pairs and distance between independent mutations in DNA. |
| Master spool number: | 6HT/72069 |
| Production number: | 00525_1173 |
| Videofinder number: | 994 |
| Available to public: | no |
