Scientists have deciphered the reason why Alfort Hopper rabbits walk with their forelegs instead of jumping with their hind legs.
The Alfort Leaping Rabbit, also known as the Alfort dancing rabbit, has a very strange way of moving. Instead of jumping with their hind legs, they use their front legs to walk and lift their hind legs off the ground like a “banana planting” movement.
Since this domestic rabbit was first discovered in 1935, scientists have wondered why they don’t move like most other rabbits.
In a new study published in the journal PLoS Genetics, geneticists led by Miguel Carneiro from the Portuguese University of Porto and Jennifer Vieillard from the Swedish University of Uppsala say they have found the answer.
Research has shown that the abnormal gait of the Alfort Leaping Rabbit is associated with a mutation in the RORB gene, resulting in the loss of glial cells in the spinal cord.
“When you move, these nerve cells work continuously. They coordinate muscle contraction and recognize whether the limbs are balanced or not. This muscle coordination does not work properly in jumping rabbits.” D’Alfort, said biologist Leif Andersson, a member of the research team.
A mutation in the RORB gene results in a deficiency or complete absence of glial cells in the spinal cord. This causes the D’Alfort Leaping Rabbit to lose the ability to move vigorously, like a long jump. The phenomenon of ‘planting bananas’ is how they adapt to not being able to jump with their hind legs. Like normal rabbits, the Sauteur D’Alfort can still crawl on all fours but at a much slower pace.
Scientists added that the D’Alfort Leaping Rabbit can learn to move quickly on its forelegs after only a few months of life and that this strange gait doesn’t hurt them.
To solve the mystery of the RORB gene mutation, Miguel and his colleagues selectively bred Alfort Hopper rabbits and identified a region of their genome that was often different from pine rabbits. This region contains 21 genes encoding proteins. The team then sequenced the gene and quickly found a mutation in the RORB gene.
“It’s the only mutation that really stands out,” says Andersson. “There are many genes that play an important role in movement and gait, but RORB is a rare case in which a mutation in a single gene produces a powerful effect.”
