All Ridges Are Not Created Equal

Variations on CORRECT RIDGES


Although rare, there are purebred Rhodesian Rdigebacks who are born without a ridge.
(Most breeders call them "ridgeless Ridgebacks. I prefer the term a friend of mine used when I referred to his puppy as a ridgeless...... He said  " I have you know that MY dog is not a ridgeless Ridgeback, it's a
South African Lion Hound! " LOL!)
Serving as the lovely models are (L) Jade and (R) Henna Moon, both
proud owners of Liz Druitt. (Actually, they were modeling their spiffy new collars in my front yard)

Nature Genetics 39, 1318 - 1320 (2007)
Published online: 30 September 2007 | doi:10.1038/ng.2007.4

Duplication of FGF3, FGF4, FGF19 and ORAOV1 causes hair ridge and predisposition to dermoid sinus in Ridgeback dogs

Nicolette H C Salmon Hillbertz1, Magnus Isaksson2, Elinor K Karlsson3,4, Eva Hellmén2,5, Gerli Rosengren Pielberg6, Peter Savolainen7, Claire M Wade3,8, Henrik von Euler9, Ulla Gustafson1, Åke Hedhammar9, Mats Nilsson2, Kerstin Lindblad-Toh3,6, Leif Andersson1,6 & Göran Andersson1

The dorsal hair ridge in Rhodesian and Thai Ridgeback dogs is caused by a dominant mutation that also predisposes to the congenital developmental disorder dermoid sinus. Here we show that the causative mutation is a 133-kb duplication involving three fibroblast growth factor (FGF) genes. FGFs play a crucial role in development, suggesting that the ridge and dermoid sinus are caused by dysregulation of one or more of the three FGF genes during development.