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Early nest environment and genes have lifetime effects on the expression of a colorful sexual signal. Joey K. Hubbard, Brittany R. Jenkins, Rebecca J. Safran Joanna.Hubbard@colorado.edu Animal Behavior Society July 30, 2013. Phenotypic Variation. Genes. Environment. Environmental change
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Early nest environment and genes have lifetime effects on the expression of a colorful sexual signal Joey K. Hubbard, Brittany R. Jenkins, Rebecca J. Safran Joanna.Hubbard@colorado.edu Animal Behavior Society July 30, 2013
Genes Environment Environmental change Phenotypic change over a short time period Selective pressure Phenotypic change over generations
Sexually-Selected Traits Indirect Benefits Direct Benefits Genetic Control Environmental Control Phenotypic Variation
North American Barn Swallows • Sexual trait • Socially Monogamous • Extra-pair paternity • Monitoring Boulder County breeding population since 2008 Safran & McGraw 2004; Safran et al. 2005
Determined paternity using microsats Pedigree 530 offspring with 111 mothers and 98 fathers
Animal Model • Univariate animal model to partition sources of variance for each color descriptor • Determine key variance components • Calculate variance ratios VP= VA + VT + VCE + VME + VR
Variance Ratios VP= VA + VT + VCE + VME + VR
Influences on Juvenile Color (Standard Error) Hubbard et al. in prep
Influences on Juvenile Color (Standard Error) Hubbard et al. in prep
Influences on Juvenile Color (Standard Error) Hubbard et al. in prep
Within-Individual Variation 54 individuals (out of ~4000 nestlings) Hatch Year Second Year 205 individuals Year 1 Year 2
Within-Individual Variation Hatch Year Second Year
Within-Individual Variation Hatch Year to Second Year
Within-Individual Variation Hatch Year to Second Year Year 1 to Year 2
Summary ✔ ✔ Genetic Variation Environmental Variation Maternal Environment
For the Swallows • Early environment has long-term effects on signal development • Females gain both indirect and direct benefits
Heritability Estimates Ignoring other sources of non-independence results in overestimation of heritability Average Brightness
Cross-fostering experiments • Experimentally tease apart effects of shared genes and shared environment • Explore specific environmental influences
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