the artificially induced expression of transgenes. For example, they are commonly used when studying chloroquine resistance produced by specialized transporter mutants. Even so the foreign expression tissue may itself confer some alterations to the expression, and so findings may or may not be entirely identical to native expression: For example, iron has been found by Bakouh et al 2017 to be an important substrate for one such transporter in X. l. oocytes, but iron is merely presumptively involved in native expression of the same gene. Online Model Organism Database Xenbase is the Model Organism Database (MOD) for both Xenopus laevis and Xenopus tropicalis. Xenbase hosts the full details and release information regarding the current Xenopus laevis genome (9.1). As pets Xenopus laevis have been kept as pets and research subjects since as early as the 1950s. They are extremely hardy and long lived, having been known to live up to 20 or even 30 years in captivity. African clawed frogs are frequently mislabeled as African dwarf frogs in pet stores. Identifiable differences are: Dwarf frogs have four webbed feet. African clawed frogs have webbed hind feet while their front feet have autonomous digits. African dwarf frogs have eyes positioned on the side of their head, while African clawed frogs have eyes on the top of their heads. African clawed frogs have curved, flat snouts. The snout of an African dwarf frog is pointed. As pests African clawed frogs are voracious predators and easily adapt to many habitats. For this reason, they can easily become a harmful invasive species. They can travel short distances to other bodies of water, and some have even been documented to survive mild freezes. They have been shown to devastate native populations of frogs and other creatures by eating their young. In 2003, Xenopus laevis frogs were discovered in a pond at San Francisco's Golden Gate Park. Much debate now exists in the area on how to exterminate these creatures and keep them from spreading. It is unknown if these frogs entered the San Francisco ecosystem through intentional release or escape into the wild. San Francisco officials drained Lily Pond and fenced off the area to prevent the frogs from escaping to other ponds in the hopes they starve to death. Due to incidents in which these frogs were released and allowed to escape into the wild, African clawed frogs are illegal to own, transport or