Nature 421, 533 - 535 (2003)

The genetic basis of family conflict resolution in mice


affilDepartment of Zoology, University of Cambridge, Downing Street,
Cambridge CB2 3EJ, UK

Asymmetries in the costs and benefits of parental investment for mothers,
fathers and offspring result in family conflict over the production and
provisioning of young. In species where females provide most resources
before and after birth, the resolution of this conflict may be influenced by
genes expressed in mothers and by maternally and paternally inherited genes
expressed in offspring. Here we disentangle these effects by means of
reciprocal mating and cross-fostering of litters between two strains of mice
that differ with respect to the typical resolution of family conflict. We
find that differences in litter size between these two strains are
determined by paternal genotype, whereas differences in provisioning are
under maternal control, showing that there is antagonistic coadaptation of
maternal and paternal effects on distinct life-history traits. Maternal
provisioning is also influenced by the type of foster offspring.
Contradictory to theoretical expectations, however, we find no evidence for
a negative correlation across strains between maternal provisioning and
offspring demand. Instead, we show that there is positive coadaptation such
that offspring obtain more resources from foster mothers of the same strain
as their natural mother, irrespective of their father's strain.

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Stuart A. Newman, Ph.D.
Department of Cell Biology and Anatomy
Basic Science Building
New York Medical College
Valhalla, NY 10595

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