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Effects of temperature extremes on genetic variances for life history traits in Drosophila melanogaster as determined from parent‐offspring comparisons
Author(s) -
Sgrò and C. M.,
Hoffmann A. A.
Publication year - 1998
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1046/j.1420-9101.1998.11010001.x
Subject(s) - fecundity , biology , offspring , heritability , genetic correlation , genetic variation , trait , maternal effect , drosophila melanogaster , evolutionary biology , genetics , demography , gene , population , pregnancy , sociology , computer science , programming language
Parent‐offspring comparisons were used to investigate the effects of temperature extremes on genetic variances for two life history traits and one morphological trait in Drosophila melanogaster . We considered three temperatures (14 °C, 25 °C and 28 °C) for culturing and testing flies, and considered heritabilities, coefficients of additive variation ( CV A ) and evolvabilities ( I A ) for fecundity, development time and wing length. For fecundity, heritabilities and evolvabilities were higher when parents were exposed to 14 °C compared to 28 °C. Parent‐offspring comparisons suggested that genetic correlations among environments were close to 1, although lower correlations were obtained in comparisons of family means. Parent‐offspring correlations across environments seemed to depend on parental temperature. For development time, heritabilities and evolvabilities were low at 14 °C compared to 28 °C. However, parent‐offspring correlations were relatively high when the progeny of parents tested at 14 °C were raised at the opposite extreme, suggesting that genetic variation can be enhanced when parents and offspring experience different conditions. CV A s and I A s for development time were lower than for fecundity, even when heritability estimates were similar in magnitude. Genetic variation for wing length was generally not affected by the temperature extremes, and genetic correlations across the extremes estimated from the parent‐offspring comparison were close to 1. There was no evidence for tradeoffs between traits; rapid development time was associated with high fecundity at both the phenotypic and genetic levels. The findings highlight inherent difficulties of estimating genetic parameters from parent‐offspring comparisons when two generations experience different environmental extremes and also show how parent‐offspring comparisons can lead to unexpected findings about the expression of genetic variation.