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Dissection and Explant Culture of Murine Allantois for the In Vitro Analysis of Allantoic Attachment
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Placentation in Marsupials.

Marilyn B Renfree1, Geoff Shaw2

  • 1School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia. m.renfree@unimelb.edu.au.

Advances in Anatomy, Embryology, and Cell Biology
|October 25, 2021
PubMed
Summary
This summary is machine-generated.

Marsupials possess a fully functional placenta, contrary to the misconception that only placental mammals have them. Decades of research confirm their unique placental specializations and reproductive capabilities.

Keywords:
ALIDDiapauseEndometriumGenomic imprintingInflammationMarsupialOmphalopleurePlacentaTammar wallabyTranscriptomeTrophoblastYolk sac

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Area of Science:

  • Reproductive biology
  • Comparative embryology
  • Mammalian evolution

Background:

  • Marsupials are often mistakenly considered "aplacental" mammals.
  • This misconception overlooks existing research on marsupial placentas.
  • Previous assumptions included a lack of maternal recognition of pregnancy and placental hormone production in marsupials.

Purpose of the Study:

  • To address the persistent misconception of marsupials as "aplacental" mammals.
  • To highlight the existence and functionality of the marsupial placenta.
  • To correct outdated views on marsupial reproductive biology.

Main Methods:

  • Review of extensive research over the last four decades.
  • Analysis of studies on marsupial reproductive systems.
  • Comparative studies of placental mammals and marsupials.

Main Results:

  • Marsupials possess a fully functional placenta.
  • Marsupial placentas exhibit unique specializations.
  • Evidence confirms maternal recognition of pregnancy and placental hormone production in marsupials.
  • Genomic imprinting has been observed in marsupials despite short gestation periods.

Conclusions:

  • Marsupials are mammals with fully developed placentas.
  • The "aplacental" classification of marsupials is inaccurate.
  • Marsupial reproductive strategies are distinct yet effective.