Multiple paternity does not depend on male genetic diversity.

Area of Science:

• Behavioral Ecology
• Evolutionary Biology
• Genetics

Background:

• Polyandry, where females mate with multiple males, is common in nature.
• The genetic diversity hypothesis suggests females engage in polyandry to increase offspring genetic variation.
• Multiple paternity is observed in house mice (Mus musculus musculus), with multiple-sired litters being more genetically diverse.

Purpose of the Study:

• To investigate whether female house mice produce multiple-sired litters when presented with genetically diverse mating opportunities.
• To test if female mating behavior is influenced by male genetic similarity, specifically non-siblings versus siblings (MHC dissimilar vs. shared MHC alleles).
• To determine if female inbreeding status affects the likelihood of producing multiple-sired progeny.

Main Methods:

• Assessed multiple paternity rates in house mice under controlled mating conditions.
• Compared mating choices between genetically dissimilar (non-sibling, MHC dissimilar) and genetically similar (sibling, shared MHC) males.
• Evaluated the effect of female inbreeding (inbred vs. outbred) on multiple paternity.

Main Results:

• Approximately 29% of litters exhibited multiple paternity.
• No significant difference in multiple paternity rates was observed when females could choose between genetically dissimilar versus similar males.
• Female inbreeding status did not influence the likelihood of producing multiple-sired litters.

Conclusions:

• The findings do not support the genetic diversity hypothesis in house mice.
• Female house mice do not appear to strategically increase multiple paternity to enhance offspring genetic diversity when given the opportunity.
• Mating behavior in female house mice may not be primarily driven by the pursuit of genetic diversity through mate choice.