The sauteur d’Alfort breed of rabbit is quite a unique breed. This lineage are known for their “handstands” where they stand upright on their hind legs due to a recessive trait in their genetic code. Since their discovery at a Parisian suburb in 1935, the reason for this phenomenon remained unknown-until now.

According to a paper published in PLOS Genetics, the trait is the product of a genetic mutation that is unique to the sauteur d’Alfort breed of rabbit. The author, Miguel Carniero, states that “The strain has been kept since then to study ocular malformations and pathological locomotion. Rabbits carrying this mutation would not be able to survive long in the wild due to its deleterious effects. This rabbit variety is also more likely to develop cataracts and become blind from this mutation”.

To learn more about this abnormality, a group of geneticists and biologists at Uppsala University in Sweeden studied rabbits that hop normally and sequenced a DNA sample. A warped gene in the DNA called RORB showed a protein in the first chromosome which caused the mutation. “With modern technology, it’s straightforward to go from a simple recessive disorder to finding the genes”, says one researcher, Leif Andersson. “The expectation was that there was something wrong with the spinal chord, because they don’t coordinate their forelegs and their hind legs”.

More specifically, the RORB protein is a transcription factor, meaning it is passed down through different genes which are further expressed in traits. The interneurons throughout the gene stop all communications throughout the body, including the “normal” hopping gene. Because RORB becomes the dominant protein, the sateur d’Alfort breed of rabbit are genetically trained to stand upon their hind legs.

Andersson continues through a scientific standpoint of humans: “What’s happening when your’e moving is that you have these neurons firing all the time, and they coordinate muscle contractions and receive feedback on the balance of different limbs. This coordination of muscle contraction is not present in these rabbits. As far as I’m aware, this mutation is causing no pain in the rabbits. It is similar to another gene, DMRT3, which disrupts the gain of mice and horses”.

Genetic science has made numerous advancements in studying the coordination of humans and animals and, after almost 90 years, the “hind legs” mystery of the sauteur d’Alfort rabbit breed has been solved. The ability to decrypt these mysteries on microscopic scales can aid in not only the development of animals, but humans as well. This shows the devastating impact genetic research has on further medical advances and society going forward.