Rabbits and other hopping animals require a functional RORB gene to move around by jumping, according to a new study by Miguel Carneiro of the Universidade do Porto and Leif Andersson of Uppsala University published March 25th in PLOS Genetics.
Rabbits, hares, kangaroos and some rodent species all travel by jumping, but this type of movement is not well understood on a molecular and genetic level. In the new paper, researchers investigated jumping-related genes using an unusual breed of domesticated rabbit called the sauteur d'Alfort. Instead of hopping, it has a strange gait where it lifts its back legs and walks on its front paws. By breeding sauteur d'Alfort rabbits with another breed and comparing the offspring's genomes and jumping abilities, the researchers identified the cause of this developmental defect. They identified a specific mutation in the RAR related orphan receptor B (RORB) gene. Typically, the RORB protein is found in many regions of the rabbit nervous system, but the mutation leads to a sharp decrease in the number of neurons in the spinal cord that produce RORB. This change is responsible for the sauteur d'Alfort's weird walk.
The new study demonstrates that a functional RORB gene is necessary for rabbits and likely other hopping animals to perform their characteristic jumping gait. The findings build on previous studies in mice, showing that animals that lack the RORB gene had a duck-like walk. Additionally, this work advances our understanding of the different ways that animals with backbones move.
"This study provides a rare example of an abnormal gait behavior mapped to a single base change and the first description of a gene required for saltatorial locomotion," the authors conclude. "It further demonstrates the importance of the RORB protein for the normal wiring of the spinal cord, consistent with previous studies in mouse."
Research Article; Peer-reviewed; Experimental study; Animals
In your coverage please use this URL to provide access to the freely available article in PLOS Genetics: http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1009429
Citation: Carneiro M, Vieillard J, Andrade P, Boucher S, Afonso S, Blanco-Aguiar JA, et al. (2021) A loss-of-function mutation in RORB disrupts saltatorial locomotion in rabbits. PLoS Genet 17(3): e1009429. https://doi.org/10.1371/journal.pgen.1009429
Funding: This work was supported by the Fundação para a Ciência e Tecnologia (FCT, https://www.fct.pt/) through POPH-QREN funds from the European Social Fund and Portuguese MCTES (CEECINST/00014/2018/CP1512/CT0002 and IF/00283/2014/CP1256/CT0012); by FEDER funds through the COMPETE program and Portuguese national funds through FCT (projects PTDC/CVT/122943/2010 and PTDC/BIA-EVL/30628/2017); by the project NORTE-01-0145-FEDER-AGRIGEN, supported by the Norte Portugal Regional Operational Programme (NORTE2020) under the PORTUGAL 2020 Partnership Agreement and through the European Regional Development Fund (ERDF); by grants from the Swedish Research Council (KK, LA), the Knut and Alice Wallenberg Foundation (LA), the Swedish Brain Foundation (KK) and the Swedish Foundation for Cooperation in Research and Higher Education (KK); and by travel grants to M.C. (COST Action TD1101). J.V. was supported by a postdoctoral contract from Stiftelsen Promobilia. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.