Human biochemical genetics / by H. Harris.

  • Harry Harris
Date:
1966
Catalogue details

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

Credit: Human biochemical genetics / by H. Harris. Source: Wellcome Collection.

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    298 THE PROBLEM OF GENE ACTION genetically determined occur normally only in certain types of tissue cells and not in others. For example, the particular component of the enzyme system phenylalanine hydroxylase, a deficiency of which occurs in phenylketonuria, is normally only present in cells of the liver. The essential point is that a gene does not exist in vacuo, but in a particular intracellular milieu, the nature of which must influence the character of the gene's activity. Many things will be involved in this. They include the cell's previous history, the nature of its immediate environment, and the functional properties of all the other genes which are present. The complete picture is clearly extremely complex and in the multicellular organism it is necessarily tied up with the whole problem of the biochemistry of development and tissue differentiation. How far current ideas about the role of genes in protein synthesis will stand the test of time remains to be seen. It must be remembered that they are based on a very restricted number of detailed examples and no doubt present concepts and working hypotheses will have to be modified considerably as investigations of a wider range of phenomena at the appropriate level of analysis become possible. In conclusion it may be said that such work as that of Ingram on the structural differences between haemoglobins A, S and C, and of Morgan and Watkins on the structural differences between the A, B, H and Le^ blood-group substances, has opened up an entirely new chapter in human genetics. It has become possible for the first time to consider inherited differences between human beings in terms of the chemical structures of particular macromolecules and the significance of this for future work can hardly be overemphasised. The appUcation of such approaches to other types of genetically determined biochemical variation will undoubtedly reveal many new perspectives, and we may expect exciting developments in the coming years. REFERENCES (1) Watson, J. D. and Crick, F. H. C. (1953 a). Nature, bond. 171, 737. (2) Watson, J. D. and Crick, F. H. C. 09536). Nature, Lond. 171, 964. GENERAL REFERENCE The Chemical Basis of Heredity, ed. McElroy, W. D. and Glass, B. Johns Hopkins Press, Baltimore, 1957.
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