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Potential for evolutionary coupling and decoupling of larval and adult immune gene expression
Author(s) -
FELLOUS SIMON,
LAZZARO BRIAN P.
Publication year - 2011
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/j.1365-294x.2011.05006.x
Subject(s) - biology , drosophila melanogaster , gene , genetics , phenotype , immune system , larva , genetic variation , transcription (linguistics) , gene expression , evolutionary biology , ecology , linguistics , philosophy
Almost all studies of the immune system of animals with metamorphosis have focused on either larval or on adult immunity, implicitly assuming that these traits are either perfectly correlated or evolutionarily independent. In this study, we use 80 crosses among 21 Drosophila melanogaster lines to investigate the degree and constancy of genetic correlation in immune system activity between larvae and adults. The constitutive transcription of Diptericin , a gene encoding a defensive antimicrobial peptide, was controlled by the same genetic factors in larvae and adults, with variation in expression determined exclusively by nonadditive genetic effects. This contrasted with another peptide‐encoding gene, Drosomycin , in which larval transcription was highly variable and determined by additive effects but adult transcription genetically invariant. We found no evidence for a fitness cost to the transcription of these genes in our study. The shared genetic control of larval and adult Diptericin transcription stands in contrast to predictions of the adaptive decoupling hypothesis, which states that distinct life‐stages should permit the independent evolution of larval and adult phenotypes. Importantly, genetic correlations between larval and adult immunities imply that parasite pressure on one life‐stage can drive the evolution of immunity (and resistance) in the other life‐stage.