Selective breeding with humans has led to some very strange and unfortunate pets over the years, and the sauteur rabbit d’Alfort is among the strangest of the lot.
This rare species of lump will not hop or walk like a rabbit or any other hare. When the sauteur is ready to go, he kicks his hind legs into the air and kicks forward on his front paws, like a human acrobat walking on their hands.
While this may sound like a funny draw, it is difficult to come up with other debilitating problems as well. Now, the one lump that can’t properly hop has helped us understand hop genetics in mammals.
Crossing a single male sauteur with one female of a New Zealand white breed and then passing on the offspring offspring, researchers picked 52 bunnies, and 23 copies of the mutant gene resembled the original father at 23 percent of them. These numbers are in line with the expected numbers when there is only one gene involved in a mutation.
Collecting the DNA of the juvenile and non-sauteur juvenile, researchers used a whole-genome sequence to compare the two groups. Eventually – as expected – there was only one gene that stood out.
The cause of the sauteur’s defective jumping seems to lie with a mutation in the evolved reserve site of a gene called RORB, which directs mammalian cells so that they can form some proteins.
RORB proteins are usually found throughout the rabbit’s nervous system, where they help convert genetic code into a protein building template. This particular shift, however, causes a particularly sharp decrease in the number of spinal neurons that can produce this protein.
Two copies of RORB mutation, of course, did not mean that there were no proteins in the spinal cord at all, and this was linked to hop inability. Other rabbits in the litter that were able to jump with their hind legs did not show such protein loss.
The RORB gene, the authors conclude, must allow rabbits to circulate. It can also be a great way for other mammal hopping.
Over the years, there has been much scientific interest in specialized biology and biomechanics that allow mammals – such as kangaroos, bunnies, hares and some mice – to hop, but the basic genetics of the feat have rarely been considered. seo.
One of the few studies out there that recently found mice with the same RORB mutation as sauteur rabbits is also unable to hop normally. Instead, these rodents weave around their front paws like a duck, with their tails and hind legs sticking up in the air.
“I spent four years watching these mice make small hand tools, and now I see a rabbit making the same hand,” said University College neurologist Stephanie Koch. London to Science News. “It’s amazing.”
Koch’s study of rabbits is the first to describe a specific gene needed for jumping or hopping, and goes very well with what she has seen in mice. mutant.
Like mutant rodents, sauteur rabbits also show other anatomical defects beyond their neural walking. Many are born blind and develop cataracts in the first year of life. RORB knockout mice also show retinal detachment.
In mice, the RORB gene appears to play a critical role in differentiating cells in the cerebral cortex and retina. It could also do something similar in the spinal cord, which is involved in the regulation of sensory and locomotion information among mammals.
So it may be this lack of protein that is causing the hind legs of rabbits and mice to pick up instead of jump. In sauteur rabbits, for example, RORB mutation appears to cause defects in differentiation between spines, although it is not clear whether this causes the neural movement.
“In addition to the expression in the spinal cord, RORB is also expressed in many regions of the brain such as the primary somatosensory cortex, auditory, visual and motor, in some thalamus and hypothalamus nuclei. , in the pituitary gland and in the advanced colliculus, ”the authors write.
“Thus, we cannot rule out the possibility that altered RORB function in the brain contributes to the locomotion phenotype characteristic for the sauteur rabbits.”
The mutated effects of RORB require further investigation, but it is clear that it is involved in some form. This was the only variant identified in the entire genome sequence of rabbits that had no effect on hopping.
While bunny hopping may involve more genes, it seems that poor sauteur rabbits certainly have guided our practice.
The study was published in Genetics PLOS.