Strange Genetic Mutation Makes Bunnies Walk On Two Legs

Geneticists have determined why an entire lineage of rabbits in France has been walking on their front legs for nearly 100 years. According to a new study, the bunny's bizarre method of locomotion is a result of stunted genetics. The recessive genetic trait was first discovered in a domesticated rabbit in a suburb of Paris in 1935.

The trait is the product of genetic mutation possibly hidden in the genetic code of the rabbit lineage for generations. The rabbit variety is known as the Alfort jumper, and in addition to walking on its front legs, it's more likely to develop cataracts and become blind. The rabbit lineage has been kept since the discovery by scientists to study ocular malformations and pathological locomotion.

Researchers note the rabbits with the mutation would be unable to survive in the wild due to the impact of the genetic mutation. When the rabbits are moving slowly, they walk on all four legs. However, when they need to move quickly, they use a method of locomotion that looks like a handstand. Recently, geneticists identified the root of all the problems in the DNA of the rabbit breed.

Scientists found the Alfort jumper had a mutation on the first chromosome called RORB that expresses a protein of the same name. Researchers say they expected to find something wrong with the spinal cord, causing a lack of coordination between the forelegs and hind legs. Scientists found that in the rabbits with the mutation, interneurons were less present or completely absent. When completely absent, the rabbits would over flex their hind legs, leaving them unable to hop.

Scientists on the project also point out that the handstand method rabbits use to move is not the mutation itself but is a workaround to the otherwise debilitating inhibition of the usual method of locomotion. Scientists note they're unaware of any pain caused by the mutation or the unorthodox method of walking on the forelegs alone.