Gestational experience alters sex allocation in the subsequent generation
A M Edwards1, E Z Cameron2, J C Pereira3
1School of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia; Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.
Royal Society Open Science
|August 6, 2016
Summary
Maternal stress during pregnancy influences offspring sex ratios in mice. Females exposed to reduced prenatal stress produced more female offspring, revealing maternal effects on mammalian reproductive strategies.
Area of Science:
- Evolutionary biology
- Reproductive science
- Maternal effects
Background:
- Adaptive maternal sex allocation hypotheses lack consistent empirical support in mammals.
- Maternal effects, influenced by maternal phenotype/genotype, may constrain offspring sex ratio adjustment via physiological changes.
- Gestational environment may play a crucial role in mediating these maternal effects.
Purpose of the Study:
- To investigate whether maternal effects, specifically a lowered gestational stress environment, constrain future parental sex allocation in laboratory mice.
- To determine if prenatal stress exposure impacts adult offspring's ability to bias litter sex ratio.
- To explore the physiological links, such as peri-conceptual glucose levels, between maternal environment and offspring sex ratio.
Main Methods:
- Laboratory mice were utilized to test the hypothesis of maternal effects constraining sex allocation.
- Females experienced a lowered stress environment during embryonic development (in utero).
- Offspring sex ratios, litter sizes, and peri-conceptual glucose levels were measured in adulthood.
Main Results:
- Females exposed to lowered prenatal stress produced female-biased litters in adulthood, without altering litter size.
- Increasing peri-conceptual blood glucose levels in these females correlated with a higher male-to-female sex ratio in their offspring.
- Prenatal stress reduction did not affect the sperm sex ratio of adult male offspring.
Conclusions:
- Maternal effects, mediated by the prenatal stress environment, can constrain offspring's capacity for sex ratio adjustment.
- Physiological factors like peri-conceptual glucose are linked to offspring sex determination, influenced by early-life stress.
- Understanding maternal effects is crucial for explaining variation in mammalian sex allocation and offspring lifelong physiology.
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