The Hx spontaneous mutation arose at The Jackson Laboratory in 1967 on the B10.D2/nSnJ background and was maintained by crossing heterozygous females to wild type littermates (Dickie, M.M. 1968). In 1987 the colony reached generation F56 and embryos were produced for cryopreservation by crossing heterozygous females to wild type males.
|Allele Name||hemimelic extra toes|
|Allele Type||Spontaneous (Modified regulatory region)|
|Gene Symbol and Name||Rr29, regulatory region 29|
|Strain of Origin||B10.D2-Hc1 H2d H2-T18c/nSnJ|
|Molecular Note||This spontaneous mutation is the result of a G-to-A transition in a conserved Shh enhancer element located in intron 5 of the Lmbr1 gene. The mutation is located 145 bp 3' of the Hxl3 mutation.|