Placental Evolution: Innovating How to Feed Babies

Area of Science:

• Evolutionary Biology
• Developmental Biology
• Genomics

Background:

• The placenta evolved from external egg resource deposition to internal gestation, fundamentally altering offspring development.
• Placental evolution is characterized by a mother-offspring resource conflict, driving a Red Queen race of diversification.
• Significant divergence exists in placental morphology, cellular processes, and function even between closely related species.

Purpose of the Study:

• To explore the genomic underpinnings of placental evolution across diverse species.
• To identify shared commonalities and critical components of placental function through comparative genomics.
• To understand the mechanisms driving rapid placental adaptation and innovation.

Main Methods:

• Comparative genomic analysis across a wide range of species, including fish and reptiles.
• Investigation of convergent evolution mechanisms in placental development.
• Analysis of gene co-option, including viral elements and signaling pathways.

Main Results:

• Convergent evolution is a recurring theme, evidenced by the co-option of envelope proteins for syncytium formation and conserved use of hormones and structural proteins.
• Endogenous retroviruses have been co-opted for transport and as mutagens, contributing to genomic innovation.
• The placental genome exhibits remarkable plasticity, facilitating rapid adaptation and evolutionary innovation.

Conclusions:

• Placental evolution is a dynamic process shaped by intergenerational conflict and repeated use of convergent mechanisms.
• Genomic plasticity and innovation within the placenta have been crucial for the evolution of complex traits, such as large brains.
• Understanding placental genomics is key to comprehending adaptations supporting offspring and mothers in changing environments.