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the total number of markers on the map to 408 (
Kukekova et al.,2011a,
2012
), 405 of which could be uniquely identified in the 7.6x genome sequence
of the dog. The resulting fox linkage map is thus directly anchored to the dog
genome sequence, enabling detailed comparisons to be made between corre-
sponding chromosomal fragments of the two species and indirect comparisons
between fox and human chromosomes. The resulting sex-averaged map com-
prises 1548.5 cM (
Kukekova et al.,2011a
) that covers 16 fox autosomes and
the X chromosome. Alignment of the fox meiotic map against the 7.6x canine
genome sequence revealed high conservation of marker order between homol-
ogous regions of the two species and provides a robust method for predicting
the chromosomal location of the fox orthologs of genes identified in the canine
or human genome sequences (
Kukekova et al., 2007, 2011a, 2012
).
MEASUREMENT OF FOX BEHAVIORAL PHENOTYPES
In the course of the selective breeding program, the behavioral phenotypes in
the selected tame and aggressive populations quickly diverged, and separate
scoring systems for assignment of fox behavioral phenotypes were developed
for the tame (
Table 10.1A
) and the aggressive population (
Table 10.1B
)
(reviewed in
Kukekova et al. 2005; Trut 1980a, b, 1999, 2001
). However, a
single, unified scoring system was required for measuring behavior in experi-
mental pedigrees descended from crosses of the tame and aggressive strains.
Individuals in such pedigrees have a wide range of behaviors and often
exhibit fragmented or reshuffled elements of the behavioral patterns charac-
teristic of the founder populations.
A new method was devised that could measure the variation in quantita-
tive behavioral phenotypes between different fox populations as well as the
resegregation of behaviors in experimental pedigrees. This new system was
rooted in the traditional behavioral test used for selective breeding (
Vasilieva
and Trut, 1990; Trut 1980b, Trut et al., 2004
, see Table 10.1). Fox responses
to humans were evaluated in a standard series of four sequential steps that
were videotaped (
Kukekova et al., 2008, 2011a
).
Step A: observer stands calmly near the closed cage but does not deliber-
ately try to attract the animal's attention;
Step B: observer opens the cage door, remains nearby but does not initiate
any contact with the fox;
Step C: observer attempts to touch the fox;
Step D: observer closes the cage door, then stays calmly near the closed
cage.
Because all foxes live under consistent conditions including similar inter-
actions with humans and because their behavior is tested at precise time
points using standard tests under constant conditions, the environmental fac-
tors that might influence behavior were held to a strict minimum.
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