(dr) R. Cavignaux / Carneiro M et al., 2021, PLOS Genetics
The jumping rabbit d’Alfort
Scientists have been able to understand what is the genetic reason that makes these very rare rabbits walk only with their front paws.
According to the website Science Alert, the d’Alfort jumping rabbit is very rare and is distinguished for walking with hind legs in the air. Although it seems like a fun feature, the truth is that it is associated with some problems that weaken the animal.
Now, the only male rabbit of this breed that is still alive has helped a team of scientists, including several Portuguese, to better understand the genetic reason behind this situation.
Researchers mated this male to a white New Zealand female and then mated the children of both. In total, the team raised 52 rabbits, of which 23% carried two copies of the mutant gene similar to that of the original rabbit.
Grouping the DNA of young jumping and non-jumping rabbits, the scientists used complete genome sequencing to compare the two groups. In the end, and as they had predicted, there was only one gene that stood out.
According to the same website, the cause of this defective way of walking appears to be a mutation in an evolutionarily conserved site of a gene known as RORB, which instructs mammalian cells to create certain proteins.
RORB proteins are generally found throughout the nervous system of rabbits, where they help to transform the genetic code into a model of protein construction. This particular mutation, however, causes a sharp decrease of the number of neurons in the spinal cord that can actually produce the protein.
In fact, two copies of the RORB mutation actually resulted in the absence of protein in the spinal cord, which was related to the rabbits’ inability to jump. Other pups of the litter capable of jumping with their hind legs did not present, in turn, this loss of protein.
Thus, the scientists concluded, in the study published on March 25 in the scientific journal PLOS Genetics, the RORB gene should be what allows rabbits to move. It may also be the key to other mammals to jump.
These conclusions are based on previous studies in rats, which showed that animals without this gene also had a different gait, similar to that of a duck.
Although more research is needed on the effects of this RORB mutation, it seems certain that it is involved in some way in this characteristic, not least because it was the only variant identified in the entire genome sequence of the rabbits that had any impact on the jump.
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