ReTro Experiences Adulthood

    Meet ReTro. He is extraordinary because he is the first cloned Rhesus monkey to reach adulthood. In the article written about ReTro on the Scientific American website, we get a full overview of the meaning of this experiment and its success. 

    ReTro was cloned the same way as Dolly the Sheep, through a process known as somatic cell nuclear transfer (SCNT). In this process, a nucleus from a somatic cell is inserted into an egg cell whose nucleus has been removed. It is noted there are extremely low survival rates with this process, which is why ReTro is so amazing to have fully developed into an adult. They had tried this experiment in 2022, but that rhesus monkey survived 12 hours after birth. At the Chinese Academy of Sciences, they researched all the errors within the cloning process. Their outcome: 484 SCNT and 499 ICSI (intracytoplasmic sperm injection) monkeys were compared, all developing through the same stages before reaching surrogates. Only 35 SCNT embryos were successfully implanted, compared to 74 ICSI embryos successfully implanted. The SCNT placentas were deformed and thick. They found SCNT embryos had serious genetic modification, resulting in a decrease in DNA methylation. To fix these issues, they used trophoblasts from ICSI embryos to form natural placentas around a cloned fetus. Once this was completed only two of the pregnancies evolved with only one survival, which we know as ReTro. Even with this success, cloning is still highly difficult, with a very low success rate. They wanted to use these animals to study drug efficacy. 

    In my opinion, it's amazing to believe we have found the basis of cloning, but not the exact way to do it yet. If universities across the globe keep putting their best foot forward in the science of genetics, there are so many things we will be able to discover and cure. If we successfully begin cloning other species, will this evolve into a future experiment with humans? Will cloning help us test genetic medical trials for illnesses? There are so many questions revolving around the process and if it is truly something we need to do. Dolly the sheep made people begin to wonder if human cloning was the next step, and if it would be humane to study. Yet Dolly was born in 1996, almost 20 years ago!

Sources:

Naddaf M, Magazine N. 2024 Jan 17. Meet ReTro, the First Cloned Rhesus Monkey to Reach Adulthood. Scientific American. https://www.scientificamerican.com/article/meet-retro-the-first-cloned-rhesus-monkey-to-reach-adulthood/.

Dolly the sheep. National Museums Scotland. https://www.nms.ac.uk/explore-our-collections/stories/natural-sciences/dolly-the-sheep/.