Early embryology; organizer cells found (Introduction)

by David Turell , Thursday, May 24, 2018, 17:40 (2375 days ago) @ David Turell

It was assumed that organizer cells existed. They have been shown on chicken embryos:

https://www.the-scientist.com/?articles.view/articleNo/54640/title/Animals--Embryonic-O...

"The organizer, a group of cells in the embryo that directs the developmental fates and morphogenesis of other embryonic cells, has been identified in human tissue for the first time, according to a study published today (May 23) in Nature. The discovery demonstrates that the organizer is evolutionarily conserved from amphibians to humans.

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"Rockefeller University embryologist Ali Brivanlou and colleagues report that when they grafted human stem cells that they’d treated with Wnt and Activin, two signaling proteins previously shown to be involved in organizer gene expression in other animals, into chick embryos, the grafted cells set off the developmental progress of the cells around them. The experiment establishes for the first time that the organizer exists in humans and that Wnt and Activin work in concert to make it possible for cells to direct embryonic development.

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"In this latest experiment, when they grafted human embryonic stem cells that they treated with Wnt and Activin into chick embryos, the stem cells caused the cells around them to begin forming a second neural axis as a line of cells running along one side of the embryo. This effectively demonstrated that Wnt and Activin signaling trigger some of the cells in early human embryos to become the organizer.

“'The beautiful thing about this is that [Brivanlou] . . . has really used cutting-edge approaches to demonstrate that this idea of the organizer, and specifically the genetic and molecular mechanisms that have been described across animal systems, can be employed in the human system,” says Daniel Kessler, a developmental biologist at the University of Pennsylvania who was not involved in the study. “This is as close as we’ll get to a definitive demonstration that these principles and mechanisms apply in the human embryo.”

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"But the discovery also has deeper meaning to him. “Human beings have always been interested in their own origins,” he says. “The amazing ability that we now have to look at our earliest moments of development and genesis is something that, to me, is as attractive—if not more—as looking at the pictures from the Hubble telescope.'”

Comment: For me the process of embryology science shows how complex it is to make an individual from a single egg. Only a desinger could create this process.