A Putative Locus for Cranial-Size Variability of the Fox (Vulpes vulpes).

Skull morphology was studied in three populations of red foxes (Vulpes vulpes): tame, which were produced by long-term selection for behavior friendly to human; aggressive, which were produced by long-term selection for aggressive behavior to human; and conventionally farm-bred, which were not deliberately selected for behavior. We have collected skull measurements from two sets of foxes: 1) 140 backcross foxes produced by breeding of tame and aggressive foxes with each other and then crossing F1 foxes to tame strain, and 2) 150 foxes from original populations (50 tame, 50 aggressive, and 50 conventionally farm-bred). The backcross foxes have been genotyped with 350 microsatellite markers and analyzed using 2B-PLS analysis. A significant correlation between microsatellite genotypes and skull shape was identified for three microsatellite markers on the tenth fox chromosome: FH2535, RVC1, and REN193M22. The second set of foxes (tame, aggressive and conventional) was genotyped for these three markers and also analyzed with 2B_PLS. A significant correlation was identified between genotypes and skull size for males, but not for females. The genomic region identified in this study contains the IGF-1 gene, which is responsible for 15% of body-size variation in dogs. Our findings suggest that the IGF-1 gene is also involved in skull-size regulation in red foxes. [ABSTRACT FROM AUTHOR]