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The programme examines the way in which a study of amino acid sequences, such as cytochrome C, can help to develop a taxonomic classification of organisms.
Metadata describing this Open University video programme
Module code and title: S299, Genetics
Item code: S299; 14
First transmission date: 20-09-1976
Published: 1976
Rights Statement:
Restrictions on use:
Duration: 00:24:30
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Producers: Jean Nunn; Hugh Tasman
Contributors: Humphrey Greenwood; John Williams
Publisher: BBC Open University
Keyword(s): Amino acid; Protein cytochrome; Amino acid sequences; Taxonomic classification
Footage description: John Williams (V/O) introduces the programme. Diagram shows several animals making up an evolutionary ladder leading to man. John Williams (V/O) explains how X-ray diffraction patterns for crystal protein molecule 5 are obtained. Shots of the apparatus and of the resulting electron density contour map. Shots of contour maps being used to build a three-dimensional model of a protein molecule. Shots of a molecular model of cytochrome C. John Williams explains why this molecule is used to study molecular evolution in animals. Using a large chart which shows the cytochrome C sequence for several organisms, Williams compares sequences for closely and more distantly related organisms. Williams, using an animation classifies organisms according to cytochrome C similarity. The animation brings out evolutionary relationships between the organisms. Williams examines a cytochrome C phyllogenetic tree. He then looks at another cytochrome C tree which is different from the first. Williams points out the differences then take another look at the contour classification above again. Humphrey Greenwood, with a taxonomic tree, explains how a classical taxonomist constructs his evolutionary classification. Greenwood discusses the problem of convergent evolution. Pectoral fins of a shark and a dolphin are compared. Film shots of dolphins swimming. Greenwood compares a dolphin fin with a human arm, then continues his discussion of taxonomic classifications. Williams explains how an ancestral protein is postulated. An animated diagram aids. Williams goes on to discuss the many different possible ways in which phyllogenetic trees can be constructed from this data. Williams examines the folding pattern of cytochrome C. He uses models of two enzymes to discuss the possibility of using folding patterns to trace the evolution of organisms. Williams points out some of the problems of this approach. Williams next looks at the relation between proteins and morphological features from the point of view of making classifications. He compares a chimp skeleton with a human skeleton, noting the pronounced differences, and then compares this with the close similarity of their proteins. Williams explains the possible reasons for these differences. Williams sums up.
Master spool number: 6HT/72142
Production number: 00525_1182
Videofinder number: 1003
Available to public: no