For the first time, scientists have used human cells to make structures that mimic the earliest stages of development, which they say will pave the way for more research without running afoul of restrictions on using real embryos. Two papers published Wednesday in the journal Nature detail how two teams of scientists independently made such structures. They stressed that their work is only for research, not reproduction, but it likely will pose new ethical questions, the AP reports. "Studying early human development is really difficult. It’s basically a black box," says Jun Wu, a stem cell biologist at the University of Texas, Southwestern Medical Center. "We believe our model can open up this field," he says, if "you can test your hypothesis without using human embryos."
Wu's team used embryonic stem cells and the second team used reprogrammed skin cells to produce balls of cells that resemble one of the earliest stages of human development. These balls, called blastocysts, form a few days after an egg has been fertilized but before the cells attach to the uterus to become an embryo. To differentiate their models from blastocysts created through fertilization, the researchers refer to the structures as "iBlastoids" and "human blastoids." Both groups stressed that the structures they made were not the same as naturally occurring embryos, and it’s unclear whether they could develop into viable embryos. Jose Polo, an epigeneticist who led the second research team, says the work could "revolutionize our understanding" of the early stages of human development, aiding research into the causes of infertility and congenital diseases.
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