Genetics of Domesticated Behavior in Dogs and Foxes - Genetics and the Behavior of Domestic Animals - page 375

puppy-like traits into adulthood, is widely used to explain behavioral, mor-
phological, and physiological changes associated with dog domestication as
well ( Coppinger and Coppinger, 2001; Wayne, 1986 ).
The multifaceted changes observed in the course of selection of foxes for
tame behavior affirm the destabilizing hypothesis of Dmitry Belyaev (1979) .
The molecular mechanisms underlying these phenomena are best addressed
by analyzing the genetic architecture of fox behavior.
IDENTIFICATION OF LOCI AND GENES IMPLICATED IN
FOX BEHAVIOR
The strains of tame and aggressive foxes provide a robust model for identifi-
cation of genes and loci involved in behavioral differences between the two
populations. Unlike modern dogs, the strain of domesticated foxes was cre-
ated rapidly by selection focused exclusively on specific behavioral traits.
Although these fox strains have been carefully studied for several decades,
only recently has it become possible to consider a systematic approach to
identify the loci and molecular mechanisms controlling these behaviors.
Classical genetic approaches to genome mapping had derived a rudimentary
map of the fox genome by 1998, with a well-defined fox karyotype
( Graphodatsky et al., 1981, 1995; Yang et al., 1999 ) and sparsely populated
linkage groups (for a review, see Rubtsov, 1998 ). To begin an attack on the
molecular genetics of behavior in these foxes, however, further resources
were essential, including a set of suitable pedigrees for mapping, an adequate
set of suitable molecular markers, and a robust method for measuring behav-
ior in resegregating pedigrees.
RESOURCES FOR MAPPING FOX BEHAVIOR
Accordingly, a program was instituted at ICG to crossbreed foxes from the
tame and aggressive strains, producing an F1 population, and subsequently
generating informative backcross and intercross pedigrees. Simultaneously,
the canine genome sequence and linkage map were exploited to identify a
set of microsatellite markers shared between the dog and the fox ( Kukekova
et al., 2004 ). Approximately 60% of canine markers proved useful for inter-
rogating the fox genome.
To construct a meiotic linkage map of the fox genome, 286 individual
foxes (180 animals in the third generation) from 37 pedigrees were geno-
typed, for a total of 320 markers ( Kukekova et al., 2007 ). A second genera-
tion of the fox meiotic linkage map was then developed using an extended
set of fox three-generation pedigrees, including a total of 916 progeny in
informative generations, and adding a further 93 microsatellite markers
adapted from dog genome sequence and the recently published genetic maps
of the dog genome ( Sargan et al., 2007; Wong et al., 2010 ). This increased