All mice used for the short-term selection (STS) were obtained from the colony at the Portland VA Medical Center, an Association for Assessment and Accreditation of Laboratory Animal Care-approved facility. All procedures were in accordance with the VA Institutional Animal Care and Use Committee and were performed according to NIH Guidelines for the Care and Use of Laboratory Animals. Mice were maintained at 21 ± 1°C in plastic cages (19 × 31 × 13 cm3) on Eco-Fresh bedding (Absorption Corp., Ferndale, WA, USA) with tap water and Purina 5001 chow (PMI Nutrition International, Brentwood, MO, USA). Pups were weaned and housed with same-sex littermates at postnatal day 21.
