https://phaidra.vetmeduni.ac.at/o:2409 Mate genetic similarity affects mating behaviour but not maternal investment in mice Auer, Kerstin E. Kerstin E. Auer 0000-0002-6399-1388 University of Veterinary Medicine Vienna Rülicke, Thomas Thomas Rülicke 0000-0002-2121-9496 University of Veterinary Medicine Vienna Dahlhoff, Maik Maik Dahlhoff 0000-0001-9189-7631 University of Veterinary Medicine Vienna Primus, Jasmin Jasmin Primus University of Veterinary Medicine Vienna Istel, Sonja Sonja Istel University of Veterinary Medicine Vienna Nature Portfolio text eng Maternal investment can affect the survival and development of offspring. Here we experimentally investigated in mice, whether females alter implantation rates and pup survival after embryo transfer depending on the genetic similarity with their vasectomised mating partner. We selected the MHC genotype and genetic background of males and paired females either with males that shared the same MHC haplotype and genetic background (CBA/J inbred males, isogenic group), that shared half of the MHC haplotype and genetic background (B6CBAF1 hybrid males, semi-isogenic group), or that had a different MHC haplotype and genetic background (C57BL/6N inbred males, allogenic group). We performed 304 pairings, resulting in 81 vaginal plugs, which confirmed mating. Plug rates were significantly higher in the semi-isogenic group (36.9%) compared to the isogenic group (19.5%), but not the allogenic group (26%). We found no difference in the number of implantation sites, the number of born or surviving pups until weaning, or litter weight or sex ratio between groups. Even though we found a mating bias, we found no difference in maternal investment under laboratory conditions. At least under pathogen-free conditions our study does not provide any evidence for differential maternal investment when females could increase offspring genetic diversity or heterozygosity. Female; Male; Animals; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Reproductiongenetics; Cell Communication; Embryo Implantation http://creativecommons.org/licenses/by/4.0/ https://phaidra.vetmeduni.ac.at/api/object/o:2409/download 10.1038/s41598-023-37547-6 https://phaidra.vetmeduni.ac.at/o:605 application/pdf Scientific Reports 13(1) (2023) Scientific Reports 13 1 707.30 kB 2023