Researchers in China have used a new technology to create genetically modified (GM) monkeys, which they claim will help to produce better models to mimic human diseases. The monkeys are being hailed as a scientific breakthrough but in reality the research is deeply disturbing.
The work was carried out using a genetic engineering system called CRISPR/Cas9 which allows researchers to cut and paste DNA to create specific mutations. Some researchers believe that this technology will allow for the creation of new models for human diseases such as Alzheimer’s and Parkinson’s. It has already been used in rats and mice but this is the first time that it has ‘succeeded’ in monkeys.
To produce just two GM monkeys, 198 eggs were collected from an unknown number of donor females and were then modified to possess three mutations using the CRISPR system. 83 embryos were found to develop the desired mutations and were subsequently surgically implanted into 29 surrogate mothers. Only ten monkeys became pregnant with a total of 19 foetuses and so far, five of the mothers have already miscarried while four are still ‘waiting’ to give birth. The ‘success’ therefore relates to only one poor female who gave birth to twins, who carry only two of the three mutations that the researchers had originally hoped for.
Instead of developing techniques that may lead to a rise in the use of monkeys in research, scientists should be focussing their efforts on the development of more human-relevant approaches. Researchers from the Hubrecht Institute in the Netherlands are already using the same technique to create genetic mutations in lab-grown human mini-organs3 while other scientists have used the system to target genes in human immune cells to investigate treatments for HIV4.
2. Generation of gene-modified cynomolgus monkey via Cas9/RNA-mediated gene targeting in one-cell embryos. (2014). Cell, 156(4): 836-843. The original article can be found here: http://www.cell.com/retrieve/pii/S0092867414000798
3. Functional repair of CFTR by CRISPR/Cas9 in intestinal stem cell organoids of cystic fibrosis patients. (2013). Cell Stem Cell; 13(6): 653-658.
4. Harnessing the CRISPR/Cas9 system to disrupt latent HIV-1 provirus. (2013). Scientific Reports; 3:2510. DOI: 10.1038/srep02510.