using reverse engineering to recreate dinosaur-like phenotypes. A GM chicken that produces the drug Kanuma, an enzyme that treats a rare condition, in its egg passed regulatory approval in 2015. Disease control One potential use of GM birds could be to reduce the spread of avian disease. Researchers at Roslin Institute have produced a strain of GM chickens (Gallus gallus domesticus) that does not transmit avian flu to other birds; however, these birds are still susceptible to contracting it. The genetic modification is an RNA molecule that prevents the virus reproduction by mimicking the region of the flu virus genome that controls replication. It is referred to as a "decoy" because it diverts the flu virus enzyme, the polymerase, from functions that are required for virus replication. Evolutionary insights A team of geneticists led by University of Montana paleontologist Jack Horner is seeking to modify a chicken to express several features present in ancestral maniraptorans but absent in modern birds, such as teeth and a long tail, creating what has been dubbed a 'chickenosaurus'. Parallel projects have produced chicken embryos expressing dinosaur-like skull, leg, and foot anatomy. Amphibians The first experiments that successfully developed transgenic amphibians into embryos began in the 1980s with Xenopus laevis. Later, germline transgenic axolotls in Ambystoma mexicanum were produced in 2006 using a technique called I-SceI-mediated transgenesis which utilizes the I-SceI endonuclease enzyme that can break DNA at specific sites and allow for foreign DNA to be inserted into the genome. Both Xenopus laevis and Ambystoma mexicanum are model organisms used to study regeneration. In addition, transgenic lines have been produced in other salamanders including the Japanese newt Pyrrhogaster and Pleurodeles watl. Genetically modified frogs, in particular Xenopus laevis and Xenopus tropicalis, are used in development biology. GM frogs can also be used as pollution sensors, especially for endocrine disrupting chemicals. There are proposals to use genetic engineering to control cane toads in Australia. Many lines of transgenic X. laevis are used to study immunology to address how bacteria and viruses cause infectious disease at the University of Rochester Medical Center’s X. laevis Research Resource for Immunobiology (XLRRI). Amphibians can also be used to study and validate regenerative signaling pathways such as the Wnt pathway. The wound-healing abilities of amphibians have many practical applications and can potentially provide a foundation for scar-free repair in human plastic surgery, such as treating the skin of burn patients.