In a first, a team of researchers hailing from the University of Georgia has managed to genetically modify reptiles by making use of the CRISPR Cas-9 gene-editing tool for creating four albino lizards.
Douglas Menke, associate professor in the department of genetics at the University of Georgia, said, ‘Reptiles are very understudied in terms of their reproductive biology and embryonic development. There are no good methods to manipulate embryos as we can easily do with mammals, fish, or amphibians. To our knowledge, no other lab in the world has produced a genetically altered reptile.’
The team says that by carrying out this particular study on lizards – Anolis sagrei or brown anoles – implications for human genetics could be achieved. In particular, eye development will benefit from this research. Why? The tyrosinase gene that has been edited using CRISPR Cas-9 gene-editing tools is the same one that gives humans the pigmentation in our skin. The enzyme is required for controlling melanin and also for eye development in humans and anoles. However, it is ‘absent in the eyes of mice and other organisms commonly used for biomedical research,’ as per the press release by the University of Georgia.
Researchers are now keenly looking for ways for manipulating this particular gene after having found a suitable animal model. This is something that was considered impossible until now. CRISPR is a gene-edition tool and was injected into the fertilized eggs of the lizards. This led to the mutation in the DNA of all of the subsequent cells. Menke’s team used microinjection technique for introducing CRISPR proteins into a number of immature eggs that were still in the ovaries of the lizards. The team injected a total of 146 immature eggs from twenty-one lizards and then waited until the eggs fertilized naturally.
Within a few weeks, the team was able to determine its success since four offspring were displaying albinism traits. This is what happens when tyrosinase has been inactivated. Student Ashley Rasys, the first author on the study, said, ‘When I saw our first albino hatchling, it was truly awe-inspiring. I’m most excited about the possibility of expanding this approach into many other reptilian model systems, effectively opening the doorway for future functional studies.’
The results of the research by the team have been published in Cell Reports.