2016/01/21 by Stephen Frankenberg, Flávia Regina Oliveira de Barros, Janet Rossant +1 · 1 citation
Medicine · Biochemistry, Genetics and Molecular Biology · #Reproductive Biology and Fertility #Genetic Syndromes and Imprinting #Pluripotent Stem Cells Research
paper · doi:10.1002/wdev.220
openalex publication_date 2016/01/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/25
The blastocyst is a mammalian invention that carries the embryo from cleavage to gastrulation. For such a simple structure, it exhibits remarkable diversity in its mode of formation, morphology, longevity, and intimacy with the uterine endometrium. This review explores this diversity in the light of the evolution of viviparity, comparing the three main groups of mammals: monotremes, marsupials, and eutherians. The principal drivers in blastocyst evolution were loss of yolk coupled with evolution of the placenta. An important outcome of blastocyst development is differentiation of two extraembryonic lineages (trophoblast and hypoblast) that contribute to the placenta. While in many species trophoblast segregation is often coupled with blastocyst formation, in marsupials and at least some Afrotherians, these events do not coincide. Thus, many questions regarding the conservation of molecular mechanisms controlling these events are of great interest but currently unresolved. For further resources related to this article, please visit the WIREs website.