Genetic variance in temperature dependent adult size deriving from physiological genetic variation at temperature boundaries |
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Authors: | Gerdien de Jong Alexandra Imasheva |
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Institution: | (1) Evolutionary Population Biology, Utrecht University, Padulaan 8, NL 3584 CH Utrecht, The Netherlands;(2) Vavilov Institute of General Genetics, Gubkin Street 3, 117809 Moscow, Russia |
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Abstract: | An increase in genetic variation in body size has often been observed under stress; an increase in dominance variance and
interaction variance as well as in additive genetic variance has been reported. The increase in genetic variation must be
caused by physiological mechanisms that are specific to adverse environments. A model is proposed to explain the occurrence
of an increase in genetic variation in body size in Drosophila at extreme temperatures. The model has parameters specific to the low- and high-temperature regions of the viable range.
Additive genetic variation in the boundary temperatures leads to a marked increase in additive genetic variation in development
rate and body size at extreme temperatures. Additive genetic variation in the temperature sensitivity in the low- and high-temperature
regions adds non-additive genetic variation. Development rate shows patterns in additive genetic variation that differ from
the patterns of genetic variation in body size; therefore, the genetic correlation between development rate and body size
changes sign repeatedly as a function of temperature. The existence of dominance in the genetic variation in the boundary
temperatures or in the low- and high-temperature sensitivities leads to a higher total genetic variance due to higher dominance
and interaction variance, for both development rate and body size.
This revised version was published online in July 2006 with corrections to the Cover Date. |
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Keywords: | biophysics body size Drosophila ectotherm genetic variance stress temperature extreme |
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