TY - JOUR
T1 - Evolution of adaptation and mate choice
T2 - Parental relatedness affects expression of phenotypic variance in a natural population
AU - Oh, Kevin P.
AU - Badyaev, Alexander V.
N1 - Funding Information:
Acknowledgments We thank R. Young, D. Acevedo Seaman, R. Duckworth, J. Good, L. Reed, E. Landeen, and two anonymous reviewers for helpful suggestions that greatly improved the manuscript. We thank J. Hubbard, T. Hamstra, E. Lindstedt, J. Merkle, L. Mizstal, R. Mui, E. Solares, and C. Secomb for help with the field-work and molecular analyses. This study was funded by grants from the NSF (DEB-0075388, DEB-0077804, IOB-0218313), the Packard Foundation, and the James Silliman Memorial Research Award.
PY - 2008/6
Y1 - 2008/6
N2 - Mating between relatives generally results in reduced offspring viability or quality, suggesting that selection should favor behaviors that minimize inbreeding. However, in natural populations where searching is costly or variation among potential mates is limited, inbreeding is often common and may have important consequences for both offspring fitness and phenotypic variation. In particular, offspring morphological variation often increases with greater parental relatedness, yet the source of this variation, and thus its evolutionary significance, are poorly understood. One proposed explanation is that inbreeding influences a developing organism's sensitivity to its environment and therefore the increased phenotypic variation observed in inbred progeny is due to greater inputs from environmental and maternal sources. Alternatively, changes in phenotypic variation with inbreeding may be due to additive genetic effects alone when heterozygotes are phenotypically intermediate to homozygotes, or effects of inbreeding depression on condition, which can itself affect sensitivity to environmental variation. Here we examine the effect of parental relatedness (as inferred from neutral genetic markers) on heritable and nonheritable components of developmental variation in a wild bird population in which mate choice is often constrained, thereby leading to inbreeding. We found greater morphological variation and distinct contributions of variance components in offspring from highly related parents: inbred offspring tended to have greater environmental and lesser additive genetic variance compared to outbred progeny. The magnitude of this difference was greatest in late-maturing traits, implicating the accumulation of environmental variation as the underlying mechanism. Further, parental relatedness influenced the effect of an important maternal trait (egg size) on offspring development. These results support the hypothesis that inbreeding leads to greater sensitivity of development to environmental variation and maternal effects, suggesting that the evolutionary response to selection will depend strongly on mate choice patterns and population structure.
AB - Mating between relatives generally results in reduced offspring viability or quality, suggesting that selection should favor behaviors that minimize inbreeding. However, in natural populations where searching is costly or variation among potential mates is limited, inbreeding is often common and may have important consequences for both offspring fitness and phenotypic variation. In particular, offspring morphological variation often increases with greater parental relatedness, yet the source of this variation, and thus its evolutionary significance, are poorly understood. One proposed explanation is that inbreeding influences a developing organism's sensitivity to its environment and therefore the increased phenotypic variation observed in inbred progeny is due to greater inputs from environmental and maternal sources. Alternatively, changes in phenotypic variation with inbreeding may be due to additive genetic effects alone when heterozygotes are phenotypically intermediate to homozygotes, or effects of inbreeding depression on condition, which can itself affect sensitivity to environmental variation. Here we examine the effect of parental relatedness (as inferred from neutral genetic markers) on heritable and nonheritable components of developmental variation in a wild bird population in which mate choice is often constrained, thereby leading to inbreeding. We found greater morphological variation and distinct contributions of variance components in offspring from highly related parents: inbred offspring tended to have greater environmental and lesser additive genetic variance compared to outbred progeny. The magnitude of this difference was greatest in late-maturing traits, implicating the accumulation of environmental variation as the underlying mechanism. Further, parental relatedness influenced the effect of an important maternal trait (egg size) on offspring development. These results support the hypothesis that inbreeding leads to greater sensitivity of development to environmental variation and maternal effects, suggesting that the evolutionary response to selection will depend strongly on mate choice patterns and population structure.
KW - Animal model
KW - Developmental stability
KW - Environmental variance
KW - Genetic complementarity
KW - Heritability
KW - Heterozygosity
KW - Maternal effects
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U2 - 10.1007/s11692-008-9017-8
DO - 10.1007/s11692-008-9017-8
M3 - Article
AN - SCOPUS:45249093560
SN - 0071-3260
VL - 35
SP - 111
EP - 124
JO - Evolutionary Biology
JF - Evolutionary Biology
IS - 2
ER -