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Diversification and conservation of the extraembryonic tissues in mediating nutrient uptake during amniote development
Author(s) -
Sheng Guojun,
Foley Ann C.
Publication year - 2012
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.2012.06726.x
Subject(s) - amniote , endoderm , biology , ectoderm , embryo , yolk sac , yolk , microbiology and biotechnology , embryogenesis , evolutionary biology , anatomy , vertebrate , genetics , ecology , embryonic stem cell , gene
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.