Monkey-human chimeras? How is this possible now? Credit: Medicalxpress

Part-Human Part-Monkey Chimeras Created In Lab

Are scientists going too far again?

Scientists have grown human cells in monkey embryos with the aim to understand how cells develop and interact with each other. As you probably know, all earlier similar attempts to create chimeras failed.

For the first time in the history of science, molecular biologists have succeeded in creating embryos that have cells of humans and macaque monkeys.

The scientists injected human stem cells into the fertilized cells of the embryos of monkeys and began to observe them. One day later, human cells were observed in 132 embryos. Ten days later – at 103, after another 19 days only three embryos remained. At the same time, the percentage of human cells in the embryos increased.

After analyzing the transcriptome of human and monkey cells taken from embryos, scientists were able to identify several new or enhanced communication pathways found in chimeric cells.

Chimeric human-monkey blatocyst. Credit: Weizhi Ji, Kunming University of Science and Technology
Chimeric human-monkey blatocyst. Credit: Weizhi Ji, Kunming University of Science and Technology

This experience provides an opportunity to create a new understanding of evolution, even despite the ambiguous ethical side of such research. Let us answer that the experiment is an important basis for the further development of new models of human biology and the study of diseases.

A professor at the Salk Institute believes that human cells in such embryos are quite difficult to take root, but if you nevertheless create chimeras using human and macaque cells as a basis, researchers will be able to figure out what exactly is an obstacle to the formation of chimeras and how these problems can be solved.

Let us clarify that experts call chimeras living organisms, which consist of a set of cells of various kinds. The basis can be different individuals of the same species or representatives of different species.

Not so long ago, in 2017, Izpisua Belmonte and his colleagues formed the 1st chimera of man and pig. Experts incorporated human cells into pig cells at an early stage of development. But they found out that they have a low molecular bond.

After this experience, scientists decided to study chimeras using a more closely related species – macaques.

This scheme shows the process undertaken by the scientists. Credit: Weizhi Ji, Kunming University of Science and Technology
This scheme shows the process undertaken by the scientists. Credit: Weizhi Ji, Kunming University of Science and Technology

Of course, all similar experiments influence serious discussions in the scientific community and beyond. People often consider them unethical and even more – useless. Not one or two renowned experts have expressed their opinion on the matter suggesting that these experiments do not give reliable data.

For example, while the cells grow successfully and develop at some rate, the chimeras do not function normally. In fact, most animals used for these experiments get sick.

In the end, there are much more ethical methods and paths to follow. For example, scientists could focus on studying human embryonic stem cell systems instead of creating human monkey chimeras. Not to mention that even if they succeed to create a grown one, the community would not accept to use of these methods.

What do you think? Should biologists continue with these attempts or should they focus on more ethical ways of studying human evolution and biology?

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Niu, Y., Sun, N., Li, C., Lei, Y., Huang, Z., Wu, J., . . . Tan, T. (2019, November 15). Dissecting primate early post-implantation development using long-term in vitro embryo culture.
ScienceDaily. (2021, April 15). Scientists generate human-monkey chimeric embryos
Subbaraman, N. (2021, April 15). First MONKEY–HUMAN embryos REIGNITE debate over hybrid animals.
Tan, T. (n.d.). Chimeric contribution of human extended pluripotent stem cells to monkey embryos ex vivo.
Wu, J. (n.d.). Interspecies Chimerism with Mammalian Pluripotent Stem Cells.

Written by Vladislav Tchakarov

Hello, my name is Vladislav and I am glad to have you here on Curiosmos. As a history student, I have a strong passion for history and science, and the opportunity to research and write in this field on a daily basis is a dream come true.

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