The selective growth by humans has led to incredibly strange and unhappy pets over the years, and the sauteur d’Alfort rabbit is among the strangest in the group.
This rare bunny does not jump or walk like any other existing rabbit or rabbit. When the rescuer is ready to leave, he puts his hind legs in the air and jumps forward on his front paws, like a human acrobat walking on his hands.
Although this may seem like a funny feature, unfortunately it comes with other debilitating problems. Now, the only bunny that can’t jump properly has helped us better understand the genetics of jumping mammals.
Crossing one jumping male with a single white female from New Zealand and then crossing the resulting offspring, the researchers raised 52 bunnies, of which 23 percent carried two copies of the mutant gene similar to the original father. These figures correspond to the expected statistics when there is a single recessive gene involved in a mutation.
Combining the DNA of the tired and non-jumping young man, the researchers used whole-genome sequencing to compare the two groups. Eventually – as they anticipated – there was only one gene that stood out.
The cause of the author’s defective jump appears to result in a mutation in a conserved evolutionary site of a gene known as RORB, which instructs mammalian cells to create certain proteins.
RORB proteins are generally found throughout the rabbit’s nervous system, where they help transform the genetic code into a model of protein construction. However, this special mutation causes a particularly sharp decrease in the number of spinal cord neurons that can actually produce this protein.
Two copies of the RORB mutation, in fact, did not lead to protein in the spinal cord, and this was related to the inability to jump. Other bedding rabbits able to jump with their hind legs did not show such a loss of protein.
The author concludes that the RORB gene must be the one that allows rabbits to bind around. It could also be the key to other mammal jumps.
Over the years, there has been a great deal of scientific interest in the special physiology and biomechanics that allow mammals – such as kangaroos, bunnies, rabbits and a few mice – to jump, but the genetics behind this have rarely been considered. .
One of the few studies out there recently found mice with the same RORB mutation as jumping rabbits also can’t jump as normal. Instead, these rodents rotate on their front paws like a duck, with their tails and hind legs glued to the air.
“I spent four years looking at these mice making small hands, and now I get to see a rabbit doing the same hand stand,” neurologist Stephanie Koch of University College London told Science News. “It is amazing.”
Koch’s study of rabbits is the first to describe a specific gene needed for jumps or jumps and aligns extremely well with what he observed in mutant mice.
Similar to mutant rodents, jumping rabbits have other anatomical defects beyond their strange gait. Many are born blind and develop cataracts in the first year of life. RORB knockout mice also show retinal degeneration.
In mice, the RORB gene appears to play a key role in differentiating cells in both the brain cortex and the retina. It might also do something similar in the spinal cord, which is involved in regulating sensory information and locomotion among mammals.
As such, this lack of protein could be what causes the hind legs of rabbits and mice to rise instead of jump. In jumping rabbits, for example, the RORB mutation appears to cause defects in spinal cord interneurons to differentiate, although it remains unclear whether this causes bizarre locomotion.
“In addition to its expression in the spinal cord, RORB is also expressed in many regions of the brain, such as the primary, auditory, visual, and motor somatosensory cortex, in some thalamus and hypothalamus nuclei, in the pituitary gland, and in the superior colic,” I write. the authors.
Thus, we cannot rule out the possibility that an alteration of RORB function in the brain may contribute to the locomotion phenotype characteristic of jumping rabbits.
The effects of the RORB mutation will require more study, but it is obvious that it is involved in some way. This was the only variant identified in the entire genomic sequence of the rabbits that had any impact on the jumps.
Although there may be several genes involved in bunny jumps, it seems that the poor rabbits have definitely pointed us in the direction of one.
The study was published in PLOS Genetics.