The squiggle tail (squig) mutation in mice is associated with a deletion in the mesenchyme homeobox 1 (Meox1) gene

We have taken a positional approach to assign the spontaneous squiggle tail (squig) mutation in mice to a specific gene defect. A large panel of backcross mice was produced and characterized to map squig to high genetic resolution on mouse Chromosome (Chr) 11. Two overlapping candidate genes that co-localized with squig (Meox1, for mesenchyme homeobox 1; and Gm11551, which encodes a lncRNA located entirely within the first intron of Meox1) were fully sequenced to discover any squig-specific defects. This analysis revealed a 3195 bp deletion that includes all of Meox1, Exon 1 but does not disrupt Gm11551. We recommend that the squig mutation be renamed Meox1squig, and suggest that this variant may offer an appropriate animal model for Klippel-Feil syndrome 2 (KFS2) in humans.