Genetics of Interactive Behavior in Silver Foxes (Vulpes vulpes).

Individuals involved in a social interaction exhibit different behavioral traits that, in combination, form the individual's behavioral responses. Selectively bred strains of silver foxes (Vulpes vulpes) demonstrate markedly different behaviors in their response to humans. To identify the genetic basis of these behavioral differences we constructed a large F population including 537 individuals by cross-breeding tame and aggressive fox strains.

Sequence comparison of prefrontal cortical brain transcriptome from a tame and an aggressive silver fox (Vulpes vulpes).

Background: Two strains of the silver fox (Vulpes vulpes), with markedly different behavioral phenotypes, have been developed by long-term selection for behavior. Foxes from the tame strain exhibit friendly behavior towards humans, paralleling the sociability of canine puppies, whereas foxes from the aggressive strain are defensive and exhibit aggression to humans. To understand the genetic differences underlying these behavioral phenotypes fox-specific genomic resources are needed.

On the origin of a domesticated species: Identifying the parent population of Russian silver foxes (Vulpes vulpes).

The foxes at Novosibirsk, Russia, are the only population of domesticated foxes in the world. These domesticated foxes originated from farm-bred silver foxes (Vulpes vulpes), whose genetic source is unknown. In this study we examined the origin of the domesticated strain of foxes and two other farm-bred fox populations (aggressive and unselected) maintained in Novosibirsk.

Effect of domestication on aggression in gray Norway rats.

A comparative analysis of intermale aggression in the resident-intruder test was conducted with gray rats from a wild unselected population bred at the laboratory for three generations and gray rats selected for elimination (tame) and enhancement (aggressive) of aggressiveness towards human for 71-72 generations. Males from the laboratory line Wistar were used as neutral opponents. Rats from the tame line were characterized by reduced aggression manifest as longer attack latency, decreased number of attacks, upright postures, chases, kicks, and shorter total time of aggressive behavior compared to unselected males.

Mapping Loci for fox domestication: deconstruction/reconstruction of a behavioral phenotype.

During the second part of the twentieth century, Belyaev selected tame and aggressive foxes (Vulpes vulpes), in an effort known as the "farm-fox experiment", to recapitulate the process of animal domestication. Using these tame and aggressive foxes as founders of segregant backcross and intercross populations we have employed interval mapping to identify a locus for tame behavior on fox chromosome VVU12. This locus is orthologous to, and therefore validates, a genomic region recently implicated in canine domestication.

Conserved methylation of the glucocorticoid receptor gene exon 1(7) promoter in rats subjected to a maternal methyl-supplemented diet.

It is well known that the early life experiences affect stress responses and other physiological and behavioral traits in adulthood. Both rat and human studies have shown that early postnatal effects are associated with methylation of the hippocampal glucocorticoid receptor gene exon 1(7) (rat) and 1-F (human) promoters. Methylation of these sites is also seen following methionine administration in adult rats.

Cross-fostering effects on weight, exploratory activity, acoustic startle reflex and corticosterone stress response in Norway gray rats selected for elimination and for enhancement of aggressiveness towards human.

Two rat lines, one tame, the other aggressive, differing by many behavioral features and stress reactivity were developed by long-term selection of wild gray rats for elimination and enhancement of aggressiveness towards humans. The aim of this work was to study the role of the maternal environment in the expression of these differences between the two rat lines using the cross-fostering paradigm. Fostering of tame rats of both sexes by aggressive mothers and aggressive females by tame mothers was without effect on behavior score towards humans, but the cross-fostered aggressive males had a small, yet significant, increase in aggressiveness score.

A meiotic linkage map of the silver fox, aligned and compared to the canine genome.

A meiotic linkage map is essential for mapping traits of interest and is often the first step toward understanding a cryptic genome. Specific strains of silver fox (a variant of the red fox, Vulpes vulpes), which segregate behavioral and morphological phenotypes, create a need for such a map. One such strain, selected for docility, exhibits friendly dog-like responses to humans, in contrast to another strain selected for aggression.