Scientists are close to solving one of science’s greatest mysteries

There has been a breakthrough in the creation of laboratory models of human embryos

Still one of science’s greatest mysteries: how a human cell—too small to be seen with the naked eye—divides and multiplies to eventually become the human body, made up of more than 30 trillion cells.

From the moment the sperm merges with the egg, the development of the human embryo includes a number of complex and poorly understood processes. Most of what is known about embryo development comes from animals such as mice, rabbits, chickens and frogs, with human embryo research being very strictly controlled and regulated in most countries.

But animal studies can only tell researchers so much. What happens during the development of a human embryo, especially in the crucial first month, remains largely unknown.

“Most of the development happens in the first month; the remaining eight months of pregnancy are mostly explosive growth,” said Jacob Hanna, professor of stem cell biology and embryology at the Weizmann Institute of Science in Israel. “But this first month is still very much a black box,” – the specialist explained.

The ability to peer into this black box will open up a world of biomedical possibilities. This could ultimately lead to a better understanding of miscarriages, birth defects and side effects of medications taken during pregnancy. And some researchers believe they have found a way to make human embryos without the need for eggs or sperm.

Using advances in stem cell technology, laboratories around the world are creating embryo-like structures—a group of cells that act like an embryo but cannot grow into a fetus.

Recent breakthroughs in the field, the culmination of years of painstaking laboratory work, have raised hope and some concern, raising pressing questions about the ethical status of these models, the extent to which they should be treated as human embryos, and whether they can be misused in scientific research. experiment.

It is possible that future stem cell-based models could recapitulate developmental milestones such as the emergence of primitive neural folds, hand buds and early stage organs (such as the heart) that would have the potential to develop into beating cardiac tissue, circulating blood and neurons, it says. In the magazine Genetics & Development in August.