# Placenta arises from two trophectoderm sources, including a previously unrecognized mural population

- Published: 2026-11-15 06:28 UTC
- Section: Life & Health › Biology & biochemistry
- Tags: placenta origin, mural trophectoderm, polar trophectoderm, embryo implantation, single-cell transcriptomics, naive and primed pluripotency, extraembryonic endoderm, stem-cell-derived embryo models, invasive trophoblast
- URL: https://realtech.media/news/rt-a801d961a014f8ec6e5ca4de_placenta_arises_from/

**Single-cell transcriptomics and live imaging in embryos at implantation showed that the placenta forms from polar trophectoderm and a mural population migrating from the polar-mural border.**

![Placenta arises from two trophectoderm sources, including a previously unrecognized mural population](https://realtech.media/media/2026/11/8a1ab34efebde7c8.jpg)
*Shuo Yang, Wikimedia Commons, CC BY 4.0*

A study in Nature Cell Biology combined single-cell transcriptomics, live imaging and functional experiments to describe cellular transitions during mammalian implantation and the start of placental formation [1]. According to the authors, implantation is the least accessible stage of mammalian development, and it is the period when most pregnancies are lost [1].

The authors identified an intermediate state between naive and primed pluripotency in the embryonic lineage. They also traced the origins of anterior-posterior axis specification to the extraembryonic endoderm and described the division of the trophectoderm into distinct placental progenitors [1].

The main finding concerns the origin of the placenta. It arises from two sources: the classically recognized polar trophectoderm and a previously unrecognized population of mural trophectoderm that migrates from the polar-mural border [1]. Human mural trophectoderm shows similar region-specific behaviour and may include progenitors biased toward invasive trophoblast, the authors report [1].

The authors state that the results may help improve stem-cell-derived embryo models and the study of early determinants of pregnancy success.

## Sources

1. [Nature Cell Biology](https://doi.org/10.1038/s41556-026-02134-0)
2. [Phys.org](https://phys.org/news/2026-11-uncovering-hidden-placenta.html)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-a801d961a014f8ec6e5ca4de_placenta_arises_from/