Instead of a sperm and egg, the starting material was naive stem cells which were reprogrammed to gain the potential to become any type of tissue in the body.
Chemicals were then used to coax these stem cells into becoming four types of cell found in the earliest stages of the human embryo:
* epiblast cells, which become the embryo proper (or foetus)
* trophoblast cells, which become the placenta
* hypoblast cells, which become the supportive yolk sac
* extraembryonic mesoderm cells
A total of 120 of these cells were mixed in a precise ratio – and then, the scientists step back and watch.
About 1% of the mixture spontaneously assembling themselves into a structure that resembles, but is not identical to, a human embryo.
They generate the cell types and then have the right environment to grow the embryo like structure.
Nature – Complete human day 14 post-implantation embryo models from naïve ES cells
This study shows other parts of the embryo will not form unless the early placenta cells can surround it.
There is talk about improving in vitro fertilization (IVF) success rates by helping to understand why some embryos fail or using the models to test whether medicines are safe during pregnancy.
The current 99% failure rate would need to be improved, otherwise researchers would not be able to differentiate the copycat embryo and the mimicking process problems from real problems.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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The article link is behind a paywall. You should link to the abstract intead: https://www.nature.com/articles/s41586-023-06604-5
> About 1% of the mixture spontaneously assembling themselves
1% of 120 cells is 1.2 cells, so I guess this should be “1% of the mixture*s*”, plural (I see the error is in the source text).
They should really be doing this with some other kind of animal, any other kind of animal. I doubt that there is something quite so special about the human embryo’s development at this early stage that a rat’s embryo won’t be indistinguishable from it.