Putative Locus for Cranial Size Variability of the Fox (<i>Vulpes vulpes</i>)

Abstract

Skull morphology was studied in three populations of red foxes (Vulpes vulpes): tame, which was produced by long-term selection for friendly behavior to humans; aggressive, which was produced by long-term selection for aggressive behavior to humans; and conventional farm-bred, which was not deliberately selected for behavior. We have collected skulls measurements from two sets of foxes: (1) 140 backcross foxes produced by breeding of tame and aggressive foxes to each other and then crossing F1 foxes to tame strain, and (2) 150 foxes from original populations (50 tame, 50 aggressive and 50 conventional 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 10-th fox chromosome: FH2535, RVC1, REN193M22. The second set of foxes (tame, aggressive and conventional) was genotyped for these three markers and also analysed with 2B_PLS. Significant correlation was identified between genotypes and skull size for males, but not for females. The genomic region identified in this study contains IGF-1 gene, which is responsible for 15% of body size variation in dogs. Our findings suggest that IGF-1 gene is also involved in skull size regulation in red foxes.