Book contents
- Frontmatter
- Contents
- Preface
- Acknowledgements
- 1 The Nature of Development
- 2 Everything Begun to the Service of Development: Cellular Darwinism and the Origin of Animal Form
- 3 Development: Generic to Genetic
- 4 Periodisation
- 5 Body Regions: Their Boundaries and Complexity
- 6 Differentiation and Patterning
- 7 Size Factors
- 8 Axes and Symmetries
- 9 Segments
- 10 Evo-devo Perspectives on Homology
- Summary and Conclusions
- References
- Index
3 - Development: Generic to Genetic
Published online by Cambridge University Press: 10 August 2009
- Frontmatter
- Contents
- Preface
- Acknowledgements
- 1 The Nature of Development
- 2 Everything Begun to the Service of Development: Cellular Darwinism and the Origin of Animal Form
- 3 Development: Generic to Genetic
- 4 Periodisation
- 5 Body Regions: Their Boundaries and Complexity
- 6 Differentiation and Patterning
- 7 Size Factors
- 8 Axes and Symmetries
- 9 Segments
- 10 Evo-devo Perspectives on Homology
- Summary and Conclusions
- References
- Index
Summary
Genes are not ‘determinants’ representing the one or the other part of the body; rather, they are modifiers of the developmental processes, intervening in this or that cellular functioning, hence in these or those morphological outcomes.
E. Guyénot 1929: 40 (my transl.)Shouldn't we do well at this stage to be flexible, rather than succumb to the current tendency for each aspect or event in an organism's life that attract our interest promptly to become the express responsibility of a gene.
J. Cooke 1980: 217Developmental Genes
Are there true ‘developmental genes’? Yes and no. Yes, in the sense that patterns of expressions of many genes are strictly limited to and correlated with specific times and events in development. Yes, in so far as mutations in these genes may critically and conspicuously alter the normal course of development. No, however, if we take any of them as directly responsible for the origin of an organ or the shaping of the body. At least we need to consider genes in context, not just with other genes, but with the whole cellular environment (Maclean and Hall 1987, Keller 2000, Nijhout 2000, Hall 2001).
I subscribe fully to Gabriel Dover's (2000: 45) text that, “There is a naivety about genetic determinism in both evolution and development that signifies intellectual laziness at best and shameless ignorance at worst when confronted with issues of massive complexity.”
- Type
- Chapter
- Information
- The Development of Animal FormOntogeny, Morphology, and Evolution, pp. 21 - 54Publisher: Cambridge University PressPrint publication year: 2003