Taken by R. Cavignaux. Image Credit: Carneiro M et al., 2021, PLOS Genetics, CC-BY 4.0
Birds fly, fish swim, horses gallop, and rabbits hop. But a rare breed of rabbit employs a unique mode of transportation: handstands. The sauteur d’Alfort rabbit walks like any other rabbit, but instead of hopping, it hikes up onto its forelegs and waddles forward when it needs to move quickly, like in the image shown here.
In a recent study published in PLOS Genetics, researchers got to the bottom of the sauteur d’Alfort’s funky walk. The team bred sauteur d’Alfort rabbits and a New Zealand rabbit breed with a normal hopping gait. Comparing the offspring’s genomes — the entirety of their DNA — they found the misbehaving gene called RORB, which creates a protein found throughout the nervous system. The hopping rabbits had a normal RORB gene, while the handstand rabbits had a mutated version. Rabbits with the mutated gene did not have any RORB protein in their spinal cord.
The absence of RORB protein may make it difficult for a rabbit to synchronize its hindlegs. And synchrony is key for a quick, coordinated movement like jumping. But scientists aren’t sure why or how a missing protein in the spinal cord encourages handstands. The loss of RORB could change the way neurons behave or eliminate them entirely. Further research will explore more of the genes responsible for different movement types and what happens when they go haywire.
Carneiro, M., Vieillard, J., Andrade, P., Boucher, S., Afonso, S., Blanco-Aguiar, J. A., Santos, N., Branco, J., Esteves, P. J., Ferrand, N., Kullander, K., & Andersson, L. (2021). A loss-of-function mutation in RORB disrupts saltatorial locomotion in rabbits. PLOS Genetics, 17(3), e1009429. https://doi.org/10.1371/journal.pgen.1009429
Garcia de Jesús, E. (2021, March 25). A gene defect may make rabbits do handstands instead of hop. Science News. https://www.sciencenews.org/article/rabbit-handstand-front-paws-gene-defect-video