What is a placental mammal anyway?

Abstract

Many developmental functions in marsupials and eutherian mammals are accomplished by different tissues, but similar genes.

The influence of evolutionary history on human health and disease

“…Evolutionary analyses of development have revealed that new anatomical structures often arise by co-opting existing structures and molecular pathways that were established earlier in the history of life. For example, animal eyes, limb structure in tetrapods and pregnancy in mammals (Box 3 ) each evolved by adapting and integrating ancient genes and regulatory circuits in new ways 35 – 38 . This integration of novel traits into the existing network of biological systems gives rise to links between diverse traits via the shared genes that underlie their development and function 36 .…”

The Role of the Epididymis and the Contribution of Epididymosomes to Mammalian Reproduction

“…In mammals, the reproductive process is sexual, fertilization usually occurs internally, and the fertilized oocyte is developed in the uterus. The placentals (or Eutheria order), with nearly 4000 described species, have some differences in terms of embryo and fetal development as compared to Monotremata and Metatheria [7,8]. In this review, we are going to briefly discuss pertinent aspects of the reproductive process of placental mammals, to provide a reproductive context for the basic science principles that will be discussed further.…”

Human milk: From complex tailored nutrition to bioactive impact on child cognition and behavior

“…In eutherian mammals, maternal energy invested in developing young prenatally (through the course of gestation via the placenta) and postnatally (via lactation and milk) is roughly equal. By contrast, marsupial gestation is brief and lactation is extended (Abbot and Capra 2017).…”

“…Included in this group are kangaroos, wallabies, koalas and opossums. Relative to eutherian mammals, marsupial mammals display short gestational periods and comparatively longer lactational periods during which a great deal of offspring development occurs supported by lactation and milk (Abbot and Capra 2017).…”