Only humans have human placentas: molecular differences between mice and humans

Area of Science:

• Reproductive Biology
• Developmental Biology
• Comparative Genomics

Background:

• The placenta exhibits high evolutionary diversity across species.
• No single animal model perfectly replicates human placentation.
• Mice are commonly used but have differences from human placentas.

Purpose of the Study:

• To evaluate the suitability of the mouse model for human placentation research.
• To discuss human-specific molecular features of the placenta.
• To assess the relevance of current animal models in light of new findings.

Main Methods:

• Comparative analysis of placental molecular features across species.
• Review of recent findings on primate-specific genetic novelties.
• Discussion of interspecies differences in placentation.

Main Results:

• Human placentation involves unique molecular features, including primate-specific genetic novelties.
• The mouse placenta, while hemochorial, differs significantly from the human placenta.
• Recent discoveries highlight limitations of the mouse model for human pregnancy research.

Conclusions:

• The mouse model is frequently overvalued for human placentation studies.
• Human-specific factors necessitate research using human cells, tissues, and subject data.
• Understanding human placentation requires approaches beyond traditional animal models.