Phenotypic plasticity

The ability of an organism with a given genotype to change its phenotype in response to changes in the environment is called phenotypic plasticity. [cite journal |author=Price TD, Qvarnström A, Irwin DE |title=The role of phenotypic plasticity in driving genetic evolution |journal="Proc. Biol. Sci." |volume="270" |issue=1523 |pages=1433–40 |year=2003 |month=July |pmid=12965006 |doi=10.1098/rspb.2003.2372 |url=http://journals.royalsociety.org/openurl.asp?genre=article&issn=0962-8452&volume=270&issue=1523&spage=1433] Such plasticity in some cases expresses as several highly morphologically distinct results; in other cases, a continuous norm of reaction describes the functional interrelationship of a range of environments to a range of phenotypes. The term was originally conceived in the context of development, but is now more broadly applied to include changes that occur during the adult life of an organism, such as behaviour.

Organisms of fixed genotype may differ in the amount of phenotypic plasticity they display when exposed to the same environmental change. Hence phenotypic plasticity can evolve and be adaptive if fitness is increased by changing phenotype. [cite journal |author=De Jong G |title=Evolution of phenotypic plasticity: patterns of plasticity and the emergence of ecotypes |journal=New Phytol. |volume="166" |issue=1 |pages=101–117 |year=2005 |month=April |pmid=15760355 |doi=10.1111/j.1469-8137.2005.01322.x] Immobile organisms such as plants have well developed phenotypic plasticity, giving a clue to the adaptive significance of plasticity. [cite journal |author=Sultan SE |title=Phenotypic plasticity for plant development, function and life history |journal="Trends Plant Sci." |volume="5" |issue=12 |pages=537–542 |year=2000 |month=December |pmid=11120476 |doi=10.1016/S1360-1385(00)01797-0]

A highly illustrative example of phenotypic plasticity is found in the social insects, colonies of which depend on the division of their members into distinct castes, such as workers and guards. [cite journal |author=Emlen DJ, Nijhout HF |title=The development and evolution of exaggerated morphologies in insects |journal="Annu. Rev. Entomol." |volume="45" |issue= |pages=661–708 |year=2000 |pmid=10761593 |doi=10.1146/annurev.ento.45.1.661] These two castes differ dramatically in appearance and behaviour. However, while these differences are genetic in basis, they are not "inherited"; they arise during development and depend on the manner of treatment of the eggs by the queen and the workers, who manipulate such factors as embryonic diet and incubation temperature. The genome of each individual contains all the instructions needed to develop into any one of several 'morphs', but only the genes that form part of one developmental program are activated. [cite journal |author=Miura T |title=Developmental regulation of caste-specific characters in social-insect polyphenism |journal="Evol. Dev." |volume="7" |issue=2 |pages=122–129 |year=2005 |pmid=15733310 |doi=10.1111/j.1525-142X.2005.05014.x]

In epidemiology, a theory is that rising incidences of coronary heart disease and type II diabetes in human populations undergoing industrialization is due to a mismatch between a metabolic phenotype determined in development and the nutritional environment an individual is subsequently exposed to. This is known as the 'thrifty phenotype' hypothesis (see evolutionary psychology).

ee also

*Developmental biology
*Evolutionary physiology

References

External links

*Special issue of the "Journal of Experimental Biology" concerning [http://jeb.biologists.org/cgi/gca?gca=209%2F12%2F2239&gca=209%2F12%2F2249&gca=209%2F12%2F2265&gca=209%2F12%2F2276&gca=209%2F12%2F2293&gca=209%2F12%2F2304&gca=209%2F12%2F2312&gca=209%2F12%2F2320&gca=209%2F12%2F2328&gca=209%2F12%2F2337&gca=209%2F12%2F2344&gca=209%2F12%2F2362&gca=209%2F12%2F2368&gca=209%2F12%2F2377&sendit=Get+All+Checked+Abstract%28s%29 phenotypic plasticity]
*Massimo Pigliucci’s Evolutionary Ecology Lab [http://www.genotypebyenvironment.org/ web page]
*"Developmental Plasticity and Evolution" - [http://www.americanscientist.org/template/BookReviewTypeDetail/assetid/29782 review of the book] from "American Scientist"

Further reading

*cite book | author=Mary Jane West-Eberhard | year=2003 | title=Developmental Plasticity and Evolution | publisher=Oxford University Press