In evolutionary biology, the variational properties of an organism are those properties relating to the production of variation among its offspring. In a broader sense variational properties include phenotypic plasticity.
[
Wagner, G. P. and Altenberg, L. 1996. Complex adaptations and the evolution of evolvability. ''Evolution'' 50 (3): 967-976.
] Variational properties contrast with functional properties. While the functional properties of an organism determine is level of
adaptedness to its environment, it is the variational properties of the organisms in a species that chiefly determine its
evolvability and
genetic robustness.
Variational properties group together many classical and more recent concepts of evolutionary biology. It includes the classical concepts of
pleiotropy
Pleiotropy () is a condition in which a single gene or genetic variant influences multiple phenotypic traits. A gene that has such multiple effects is referred to as a ''pleiotropic gene''. Mutations in pleiotropic genes can impact several trait ...
,
canalization,
developmental constraints,
developmental bias,
morphological integration,
developmental homeostasis and later concepts such as
robustness
Robustness is the property of being strong and healthy in constitution. When it is transposed into a system
A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, ...
,
neutral networks,
modularity
Modularity is the degree to which a system's components may be separated and recombined, often with the benefit of flexibility and variety in use. The concept of modularity is used primarily to reduce complexity by breaking a system into varying ...
, the
G-matrix and
distribution of fitness effects.
Variational properties also include the production of DNA sequence variation, epigenetic variation, and phenotypic variation. While the genome is typically thought of as the storehouse of information that generates the organism, it can also be seen as the set of heritable degrees of freedom for varying the organism. DNA thus has both a generative role in the organism, and variational role in the lineage.
References
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Evolutionary biology terminology