Behavioral and reproductive differences in mice as a function of inbreeding

Area of Science:

• Genetics
• Animal Behavior
• Reproductive Biology

Background:

• Inbreeding, the mating of closely related individuals, can reveal the effects of recessive alleles.
• Understanding the impact of inbreeding is crucial for conservation genetics and animal breeding programs.

Purpose of the Study:

• To investigate the effects of progressive inbreeding on reproductive behavior, learning, and locomotor activity in mice.
• To quantify the decline in various fitness and behavioral parameters across six generations of brother-sister mating.

Main Methods:

• Brother-sister mating was employed for six generations, achieving a coefficient of inbreeding (F) up to 0.732.
• Reproductive indices (fertile matings, offspring survival, pup weight) and behavioral tasks (active avoidance learning/extinction, passive avoidance retention, locomotor activity) were assessed.

Main Results:

• A consistent decline was observed in fertile matings, offspring survival to weaning, and pup weight at weaning.
• Learning an active avoidance task required more trials, while habituation to this task occurred faster with increased inbreeding.
• Passive avoidance retention showed statistically significant but variable differences across generations; locomotor behavior was largely unaffected.

Conclusions:

• Progressive inbreeding negatively impacts reproductive success and modifies learning and memory processes in mice.
• The observed behavioral changes suggest that inbreeding affects neural pathways involved in learning and habituation.
• While reproductive and learning behaviors are sensitive to inbreeding, locomotor activity appears more robust.