Molecular conservation of marsupial and eutherian placentation and lactation.

Michael W Guernsey,Julie C Baker,Marilyn B Renfree,Edward B Chuong,Guillaume Cornelis

doi:10.7554/elife.27450

Michael W Guernsey, Julie C Baker + Show 3 more

Open Access

https://doi.org/10.7554/elife.27450

Copy DOI

Abstract

Eutherians are often mistakenly termed 'placental mammals', but marsupials also have a placenta to mediate early embryonic development. Lactation is necessary for both infant and fetal development in eutherians and marsupials, although marsupials have a far more complex milk repertoire that facilitates morphogenesis of developmentally immature young. In this study, we demonstrate that the anatomically simple tammar placenta expresses a dynamic molecular program that is reminiscent of eutherian placentation, including both fetal and maternal signals. Further, we provide evidence that genes facilitating fetal development and nutrient transport display convergent co-option by placental and mammary gland cell types to optimize offspring success.

Highlights

While placental morphology varies widely between different mammalian species, its functions as a center for embryonic respiration, nutrient uptake, waste removal and embryonic signaling are highly conserved (Cross, 2006)
The bilaminar omphalopleure (BOM) up-regulated genes are associated with ontology related to endocytosis and metabolism (p-adj = 0.0764, 0.0390, see Supplementary file 1) consistent with the hypothesis that BOM acts as the center for embryonic nutrient uptake (Renfree, 1973b)
While we demonstrate that the tammar placental transcriptome shares molecular similarities to the term eutherian placenta, the mouse and human placenta are molecularly distinct between the first half and second half of pregnancy, with the early stages primarily involved in cell cycle and metabolism and the later stages focused on reproduction (Knox and Baker, 2008; Winn et al, 2007)

Summary

Introduction

While placental morphology varies widely between different mammalian species, its functions as a center for embryonic respiration, nutrient uptake, waste removal and embryonic signaling are highly conserved (Cross, 2006). Given this diverse set of tasks, it is intriguing how an organ with such great morphological diversity performs the same function across widely divergent taxa. While the diversity of invasion is extreme between therian species, it is only one of the many functional, cellular, and morphological differences in placentation This extreme diversity raises interesting questions about how a wide array of structures and cell types can mediate something as complex as fetal development

Methods

Results

Discussion

Conclusion