TY - JOUR
T1 - The genetic architecture of immune defense and reproduction in male Bombus terrestris bumblebees
AU - Wilfert, Lena
AU - Gadau, Juergen
AU - Schmid-Hempel, Paul
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2007/4
Y1 - 2007/4
N2 - Understanding the architecture of genetic variation, that is the number, effect, location, and interaction, of genes responsible for phenotypic variability in nature is important for the understanding of microevolutionary processes. In this study, we have used a quantitative trait loci (QTL) approach to uncover the genetic architecture of fitness-relevant traits associated with reproduction and immune defense in male Bombus terrestris bumblebees. Three male reproductive investment traits, the number and length of the produced sperm and the size of the accessory glands, were studied. Two branches of the insect innate immune system, the activation of the Phenoloxidase-cascade and the hemolymph's antibacterial activity, were investigated. We found that variation in most of the studied traits is based on a network of minor QTLs and epistatic interactions. Unexpectedly, there was no evidence for phenotypic or genetic trade-offs between the presumably costly investment in immune defense and reproductive effort in this population for the measured traits. In fact, we found a positive correlation, both, in phenotype and genetic architecture for the number of produced sperm and antibacterial activity against an insect pathogen. A major finding for all traits analyzed was that the epistatic interactions accounted for a major proportion of the explained phenotypic variance. Especially for traits involved in immune defense, this pattern highlights the possible role of parasites in the evolution and maintenance of recombination and sexual reproduction.
AB - Understanding the architecture of genetic variation, that is the number, effect, location, and interaction, of genes responsible for phenotypic variability in nature is important for the understanding of microevolutionary processes. In this study, we have used a quantitative trait loci (QTL) approach to uncover the genetic architecture of fitness-relevant traits associated with reproduction and immune defense in male Bombus terrestris bumblebees. Three male reproductive investment traits, the number and length of the produced sperm and the size of the accessory glands, were studied. Two branches of the insect innate immune system, the activation of the Phenoloxidase-cascade and the hemolymph's antibacterial activity, were investigated. We found that variation in most of the studied traits is based on a network of minor QTLs and epistatic interactions. Unexpectedly, there was no evidence for phenotypic or genetic trade-offs between the presumably costly investment in immune defense and reproductive effort in this population for the measured traits. In fact, we found a positive correlation, both, in phenotype and genetic architecture for the number of produced sperm and antibacterial activity against an insect pathogen. A major finding for all traits analyzed was that the epistatic interactions accounted for a major proportion of the explained phenotypic variance. Especially for traits involved in immune defense, this pattern highlights the possible role of parasites in the evolution and maintenance of recombination and sexual reproduction.
KW - Epistasis
KW - Natural variation
KW - QTL
KW - Recombination
KW - Trade-off
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U2 - 10.1111/j.1558-5646.2007.00079.x
DO - 10.1111/j.1558-5646.2007.00079.x
M3 - Article
C2 - 17439613
AN - SCOPUS:34047209040
SN - 0014-3820
VL - 61
SP - 804
EP - 815
JO - Evolution
JF - Evolution
IS - 4
ER -