The intimate relationship between mother and fetus allows placental mammals to birth live offspring.
Compared to our egg-laying ancestors, this evolutionary step affords the fetus greater protection within the mother, and has led to a dramatic expansion in brain development.
But it might surprise you to know that an ancient retrovirus was, in part, responsible for this breakthrough.
The syncytiotrophoblast (depicted in the second panel):
⚆ A acts as a barrier between the placenta and the maternal tissue.
⚆ Contains a protein called syncytin that allows this barrier to form, and which originated from the envelope protein of a retrovirus!
⚆ is essential to maintain a close relationship where nutrients and gases can be exchanged, whilst ensuring feto-maternal tolerance and immune suppression.
⚆is a multinucleate cell layer of fetal origin.
Thank you to 🇪🇸 Antonio García Gómez. Antonio, holds a PhD in Biochemistry and he is a scientific illustrator passionate about translating scientific messages into effective and engaging illustrations.