Key Takeaways
- Colossal Biosciences aims to create a moa by genetically altering chickens, the only birds currently suitable for genetic engineering.
- The company has developed an artificial eggshell to address the yolk size limitations for growing moa embryos.
- Challenges include the genetic modifications and potential survival issues of moa embryos in chicken eggs, but the artificial egg provides a solution.
Genetic Innovation in Avian Science
Colossal Biosciences is exploring the intricate details of mammalian pregnancy to enhance their project aimed at resurrecting the extinct moa. Central to this endeavor is the development of an artificial eggshell, which serves as a technical breakthrough. This innovation is rooted in the ability of chickens to support ex utero development; once an egg is laid, an embryo begins to develop by drawing nutrients from the yolk, the egg white, and the shell.
To recreate the moa, which is a large flightless bird from New Zealand, Colossal plans to genetically alter a different bird species. This process involves modifying thousands of DNA letters, which can only currently be undertaken with chickens. The alteration process requires sophisticated techniques that edit avian stem cells responsible for producing eggs and sperm. The edited stem cells are then injected back into a chicken egg, allowing the resultant bird to inherit these genetic modifications.
Pask, a key figure at Colossal, speculated about the possibility of modifying chick stem cells to produce sperm or eggs resembling those of a moa. This might lead to a unique scenario where a chicken could lay an egg containing a moa embryo, although the egg itself would still be chicken-derived.
Helen Sang, a professor emeritus at the Roslin Institute, raised concerns about whether a moa embryo could thrive on the yolk of a chicken egg. The evolutionary differences pose significant challenges, particularly due to the size disparity between chicken yolks and the larger requirements of moa embryos. Pask acknowledges these challenges but believes the artificial egg can effectively address them.
He explained that one potential solution involves using a fine needle to combine multiple yolks, thereby creating a more substantial yolk mass for the moa embryo. While chicken eggs may not provide enough nutrition for the entire term, transferring the developing egg to an artificial environment may facilitate growth to hatching size.
So far, the artificial egg has shown promising results with chickens, so much so that the company has temporarily halted the hatching process due to an overwhelming number of chickens successfully developing. The team is keen to refine their approach as they navigate the complexities of avian genetic engineering and the ambitious goal of reviving the moa species.
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