This paper demonstrates the influence of artificial selection on morphometric traits in the red fox [Vulpes vulpes (Linnaeus, 1758)]. Measurements and two proportion coefficients were analysed in 132 wild and 199 farm red foxes. The two groups differed significantly (P ≤ 0.05) on all but one of the measurements. Eight out of 11 measurements were significantly greater in the farm fox population, while only tail length, ear height, and length of the right hind limb were greater in the population of wild foxes. The opposite trend was observed when analysing variation in the measurements -the farm foxes were characterized by a greater variability only in the case of body weight, body length, and breadth of chest. When analysing the sexual dimorphism index in different sex and population groups, in almost all analysed traits, the greatest differences occurred between farm males and wild females. All of the traits examined in this study are important for survival of wild foxes. However, because importance of some traits was reduced during domestication and selective breeding (farm foxes do not have to fight for survival), the genetic relationship between them may have weakened. Other possible causes of morphological differences between the studied groups of red foxes are discussed as well.Key words: morphometrics, farm red fox, wild red fox, Vulpes vulpes.Résumé : Cet article démontre l'influence de la sélection artificielle sur les caractéristiques morphométriques du renard roux [Vulpes vulpes (Linnaeus, 1758)]. Des mesures ainsi que deux coefficients de proportion ont été analysés chez 132 renards roux sauvages et 199 renards roux d'élevage. Les deux groupes différaient de façon significative (P ≤ 0,05) sur toutes les mesures sauf une. Huit des 11 mesures étaient significativement plus élevées dans la population de renards d'élevage, tandis que seulement la longueur de queue, la hauteur des oreilles et la longueur de la patte droite arrière étaient plus élevées dans la population de renards sauvages. Une tendance inverse a été observée lorsqu'il y a eu analyse de la variation dans les mesures -les renards d'élevage se caractérisaient par une plus grande variabilité seulement dans le cas du poids corporel, de la longueur du corps et de la largeur de poitrine. Lors de l'analyse de l'indice de dimorphisme sexuel parmi les différents groupes sexe et population, dans la plupart des caractéristiques analysées, les plus grandes différences se retrouvent entre les mâles d'élevage et les femelles sauvages. Toutes les caractéristiques examinées lors de cette étude sont importantes pour la survie des renards sauvages. Par contre, puisque l'importance de certaines caractéristiques est diminuée pendant la domestication et l'élevage sélectif (les renards d'élevage ne sont pas obligés de se battre pour leur survie), la relation génétique entre eux pourrait avoir faibli. D'autres causes possibles des différences morphologiques entre les groupes de renards roux étudiés sont aussi discutées. [Traduit par la Rédaction] Mots-...

The skulls of 165 red foxes (75 wild and 90 farm-bred individuals) collected in Poland in the years 2012-2014 were measured, analysed, and compared to further investigate the effect of ancestry and selective breeding on craniometrical variation between wild and farm red fox populations. Univariate comparisons of skull measurements (19 cranial traits), as well as four craniometric indices, revealed significant differences among vast majority of the studied measurements. Principal component analyses and two-dimensional plots showed almost complete separation of the two studied populations of the red fox, as well as clear separation of sexes between populations and within the farm population. This may suggest that the selective forces (artificial vs. natural selection) acting upon cranial morphology of the red fox vary between wild and farm populations. Furthermore, the second important factor which cannot be ignored when considering morphological differences between wild and farm foxes is the origin of compared populations (the Eurasian wild red fox population vs. the red foxes of North American origina founder population of farm foxes). Thus, the ancestry of the farm foxes is discussed as well. Résumé : Les crânes de 165 renards roux (75 sauvages et 90 d'élevage) collectés en Pologne dans les années 2012 à 2014 ont été mesurés, analysés et comparés pour étudier davantage les effets d'ascendance et de reproduction sélective sur les variations craniométriques entre les populations de renards roux sauvages et d'élevage. Les comparaisons unidimensionnelles des mesures de crânes (19 caractéristiques crâniennes) ainsi que quatre indices craniométriques ont révélé des différences significatives dans la vaste majorité des mesures étudiées. Des analyses en composantes principales et des graphiques en deux dimensions montraient une séparation presque complète des deux populations étudiées de renard roux ainsi qu'une séparation nette des sexes entre les populations, et à l'intérieure de la population d'élevage. Ceci pourrait suggérer que les forces de sélection (sélection artificielle c. naturelle) qui agissent sur la morphologie du crâne des renards roux varient entre les populations sauvages et d'élevage. De plus, le deuxième facteur important qui ne peut pas être ignoré lors de la considération des différences morphologiques entre les renards sauvages et d'élevage est l'origine des populations comparées (la population eurasienne de renards roux sauvages c. les renards roux d'origine nord-américaineune population fondatrice des renards d'élevage). Donc, l'ascendance des renards d'élevage est discutée aussi. [Traduit par la Rédaction]Mots-clés : craniométrie, renard roux d'élevage, renard roux sauvage, Vulpes vulpes.

Polymorphism of 30 canine-derived microsatellites was studied in a group of 200 red foxes kept on 2 Polish farms. 22 out of 30 microsatellites were selected to study association between marker genotypes and body weight (BW), body length (BL), body circumference (BC), tail length (TL), ear height (EH), length of the right front limb (FRLL), length of the right rear limb (RRLL), length of the right front foot (FRFL) and length of the right rear foot (RRFL). A total of 112 alleles and 243 genotypes were found at 22 autosomal microsatellite loci. Three monomorphic loci deemed as uninformative were excluded from the study. The association between marker genotypes and the studied traits was analysed using general linear model (GLM) procedure and least squares means (LSM). Linkage disequilibrium (LD) was estimated to assess non-random association between microsatellite loci. Out of 19 microsatellites studied four markers showed no association with the studied traits, three markers had a significant effect on one trait, and another three markers had significant effect on two traits. Among ten microsatellites with significant effect on four economically important traits (BW, BL, BC, TL) four were associated with two characters: marker FH2613 with BW and BC, marker FH2097withBL and BC, marker ZUBECA6 with BW and BC, whereas marker REN75M10 was associated with BL and TL. The strongest LD (r2 ranged from 0.15 to 0.33) was estimated between nine loci with significant effect on economically important traits (BW, BL, BC, TL).

A number of studies showed that many mtDNA haplotypes were shared among contemporary farm red foxes bred on different continents and the historical wild red foxes of North American origin. Therefore, in this study, the population genetic structure and phylogeographic relationships of Polish red foxes kept on fur farms and their wild conspecifics were investigated to assess the ancestry of the farm red foxes in Poland. A total of 330 tissue samples (200 from farm foxes and 130 from wild foxes) were used for the genetic analyses. Thirty microsatellite loci and two regions of mtDNA were used to assess the level of admixture between farm‐ and wild red foxes, to construct haplotype networks and create a phylogenetic tree. The genetic structure analysis clearly indicated two genetic clusters as being the most probable number of genetically distinct populations. The fixation index revealed a significant genetic distance between the farm‐ and wild red fox populations (FST = 0.27, p < 0.05). Haplotype networks based on frequencies showing relationships between concatenated haplotypes of Polish farm‐ and wild red foxes and the constructed phylogenetic tree clearly indicated two genetically distinct groups. The results of this study provide strong evidence confirming the North American origin of red foxes bred on Polish farms and the genetic distinctiveness of both studied populations.

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