In a dazzling reptilian, researchers were able to genetically engineer a reptile embryo using the gene modification technique called CRISPR. The technology has been used for fish, birds, amphibians and even mammals, but this is the first time scientists have introduced squamates – lizards and snakes – into the picture.
Squamates have been excluded from most CRISPR experiments because of their unique sexual reproductive process. CRISPR works through a cocktail of specialized DNA strands and enzymes that cut other pieces of DNA, usually injected directly into an egg after fertilization. But female squamates store sperm internally for long periods of time and form a brittle shell around the embryos once they are fertilized. It is therefore difficult for researchers to know exactly when to inject their carefully calibrated gene editing mix.
Scientists at the University of Georgia have turned to immature eggs, or oocytes, female anole, a type of lizard native to the Caribbean. How did they do it? Lizard operation, complete with an operating table and anesthesia. They accessed the anole of anole and gently injected the CRISPR cocktail into its oocytes. One of the genes modified in the study, which appeared on Sunday on the bioRxiv preprint server, targeted the pigmentation of lizards, which makes it clear whether splicing has worked on embryos.
After a few lizard mating, the anole females started to lay CRISPR-modified fertilized eggs. And now some descendants hatched into venerable ghost lizards, as stated above – the so-called "crispy" embryos, have been a success.
The researchers are excited about what this could mean for the study of reptilian genetics. As Jon Cohen reports for Science, a gecko biologist called the discovery "game changer". This experiment created a model for splicing the DNA of lizards and snakes without waiting for fertilization of the embryo.
Douglas Menke, one of the researchers in the study, tweeted Monday: "We can finally explore the rich biology of gene function in reptiles."