Scientists show for first time how early human embryo acquires its shape

July 19, 2011

How is it that a disc-like cluster of cells transforms within the first month of pregnancy into an elongated embryo? This mechanism is a mystery that man has tried to unravel for millennia.

The first significant step towards understanding the issue was made nearly a century ago in experiments conducted by the German embryologists Hans Spemann and Hilde Mangold. The two used early newt embryos and identified a group of cells within them which, upon transplantation, formed a two-headed tadpole.

In trying to understand why this happened, they concluded that what occurred is that the transplanted cells organized the vicinity into which they were placed to form a typical embryonic shape. They therefore dubbed such cells "organizer" cells. The newt embryo possessed both its own organizers and the transplanted ones, both of which organized nearby cells to form a head structure.

Recently, Israeli scientists from the Hebrew University of Jerusalem have managed to generate human organizer cells, using human . Based on the similarity that dominates the initial of all vertebrates, the group raised the human cells in conditions which recapitulate those of early amphibian . Within two days, the human cells started expressing genes characteristic of the organizer cells.

To verify that these cells derived from posses a true organizing ability, the researchers repeated Spemann and Mangold's experiments. Only this time, the human cells, rather than those of amphibians, were transplanted into frog embryos.

The midline of an amphibian embryo is marked by a – a tissue destined to form the embryo's central nervous system. To the group's astonishment, some of the frog embryos that were transplanted with the human cells possessed not one but two neural tubes. The second tube was composed from frog cells, proving that the injected organized the cells in their vicinity to acquire a tubular shape.

Related Stories

Recommended for you

Flu study, on hold, yields new vaccine technology

September 2, 2015

Vaccines to protect against an avian influenza pandemic as well as seasonal flu may be mass produced more quickly and efficiently using technology described today by researchers at the University of Wisconsin-Madison in the ...

We've all got a blind spot, but it can be shrunk

August 31, 2015

You've probably never noticed, but the human eye includes an unavoidable blind spot. That's because the optic nerve that sends visual signals to the brain must pass through the retina, which creates a hole in that light-sensitive ...

Biologists identify mechanisms of embryonic wound repair

August 31, 2015

It's like something out of a science-fiction movie - time-lapse photography showing how wounds in embryos of fruit flies heal themselves. The images are not only real; they shed light on ways to improve wound recovery in ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.