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Exposure to a novel environment in conjunction with serial bottlenecks increases phenotypic and additive variation of a quantitative trait

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Author(s): T.E. Callicrate | R.C. Fleischer | F. Siewerdt

Journal: Genomics and Quantitative Genetics
ISSN 2157-9903

Volume: 5;
Issue: 1;
Start page: 5;
Date: 2012;
Original page

Keywords: additive variance | population translocation | Tribolium castaneum

ABSTRACT
Demographic bottlenecks were replicated in laboratory conditions using Tribolium castaneum in order to determine how additive genetic variance, and therefore adaptive potential, may be affected by a novel environment. A two-level bottleneck was imposed. The first level was a 100-individual bottleneck (five replicates). After three generations at population size 100, the second bottleneck consisted of a single mating pair (15 sub-replicates stemming from each first-level replicate). Two growth media (environments), standard (wheat flour) or novel (wheat bran), were used in the sub-replicates to simulate translocation to an environment with a different foraging substrate. Sub-replicates were managed for slow population growth during six generations to population size 50 and were thus maintained for nine additional generations. Variance in pupa weight in generation 16 was affected by drift from the first and second-level bottlenecks (flour: N=382, bran: N=470 pupae, both P < 0.0001 at each bottleneck level). Total phenotypic variance was determined from the progeny of the single pair matings and was larger for bottlenecks occurring in bran than in flour, P < 0.01 (F469,381 = 1.29). Additive variance was also larger in bran than flour bottlenecks, P < 0.01 (F469,381 = 1.38). These results indicate that bottlenecks occurring in a novel environment could potentially increase the effectiveness of selection by bolstering additive variance.
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