Microscopy images from: A physiological and histological atlas of reproduction in the North American deer mouse (Peromyscus maniculatus)

The North American deer mouse (Peromyscus maniculatus) exhibits extensive
diversity in morphology, physiology, and life history across its broad
range. These traits have propelled the deer mouse to model system status
across several fields within the biological sciences. Nonetheless, we
still lack basic knowledge about some important aspects of this species’
biology. For example, limited information about the deer mouse’s
reproductive physiology remains a significant barrier to developing
genetic tools for the species and for advancing our current understanding
of how this species has been so evolutionarily successful. In this
manuscript, we aim to fill this knowledge gap by (1) characterizing body
temperature profiles across reproductive stages and (2) generating a
detailed histological atlas of placental development. We show that body
temperature can be used to diagnose copulation and pregnancy in deer mice,
however body temperature cannot be used to predict fertility (likelihood
to breed) prior to pairing individuals. Our placental atlas represents the
first day-by-day developmental timeline of the placenta in a Peromyscus
species, and from it we are able to describe unique organization and
behaviors of trophoblast cells, especially at the maternal-fetal interface
in the deer mouse. Together, these descriptive datasets provide
substantial new comparative data on reproductive physiology in Cricetids,
and they provide a foundation for further functional work in this
important model species.