Developmental Plasticity, Evolution and the Origins of Disease

Published on October 1, 2007 Reviewed on May 31, 2016   31 min

Other Talks in the Series: Evolution and Medicine

0:00
This lecture is about the connections between developmental plasticity, evolution, and the origins of disease. My name is Mary Jane West-Eberhard, and I work for the Smithsonian Tropical Research Institute in Panama, while living most of the time in Costa Rica. I confess that I am not a medical researcher. I am an evolutionary biologist. My research is primarily field work on the natural history and behavior of tropical social wasps.
0:24
Observations on these exquisitely conditioned sensitive organisms led first to an interest in the origin of workers and queens.
0:32
Which of these two forms, as developed by an individual female, is environmentally determined? From studying these, I got interested in developmental plasticity in general.
0:44
Developmental plasticity is simply the responsiveness of the phenotype to new inputs from the external or the internal environment. It's phenotypic change without genetic change.
0:56
The word phenotype, of course, refers to all traits of an organism other than its genes. This includes molecular products of genes, morphology, physiology, and behavior, including learned traits. It includes nervous tics, remembered phone numbers, and spots on the lung following a bout with the flu. That is, phenotypes can be adaptive or pathological, permanent or temporary, and typical or atypical of a species.
1:23
Developmental plasticity is a broader concept than phenotypic plasticity. Phenotypic plasticity is responsiveness to the external environment. Developmental plasticity includes responses to the internal environment. This means that includes sensitivity to things like gene products within cells and the action of hormones on tissues. Developmental plasticity includes modularity of structure.
1:48
Have you ever wondered how it can be that men and women with strikingly different faces can mate with each other, and yet all the different pieces somehow fit together in their offspring to make a coherent face? This is because the different pieces of the face are semi-independently developed, or modular, as shown in the side. And there is accommodation among adjacent bones other tissues. So modularity is a kind of internal plasticity during development. Since my main field of research is actually on the evolution of insect social behavior, I usually try to avoid extrapolating to humans. But I don't worry much about this in the case of developmental plasticity. Because it's a universal property of living things, almost a defining property of life.
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