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Diversification and conservation of the extraembryonic tissues in mediating nutrient uptake during amniote development
Article first published online: 10 OCT 2012
© 2012 New York Academy of Sciences.
Annals of the New York Academy of Sciences
Volume 1271, Nutrition and Physical Activity in Aging, Obesity, and Cancer pages 97–103, October 2012
How to Cite
Sheng, G. and Foley, A. C. (2012), Diversification and conservation of the extraembryonic tissues in mediating nutrient uptake during amniote development. Annals of the New York Academy of Sciences, 1271: 97–103. doi: 10.1111/j.1749-6632.2012.06726.x
- Issue published online: 10 OCT 2012
- Article first published online: 10 OCT 2012
- chorioallantoic placenta;
- yolk sac endoderm;
- extraembryonic tissues
The transfer of nutrients from the mother through the chorioallantoic placenta meets the nutritional needs of the embryo during human prenatal development. Although all amniotes start with a similar “tool kit” of extraembryonic tissues, an enormous diversity of extraembryonic tissue formation has evolved to accommodate embryological and physiological constraints unique to their developmental programs. A comparative knowledge of these extraembryonic tissues and their role in nutrient uptake during development is required to fully appreciate the adaptive changes in placental mammals. Here, we offer a comparative embryological perspective and propose that there are three conserved nutrient transfer routes among the amniotes. We highlight the importance of the yolk sac endoderm, thought to be a vestigial remnant of our amniote lineage, in mediating nutrient uptake during early human development. We also draw attention to the similarity between yolk sac endoderm-mediated and trophectoderm-mediated nutrient uptake.