identification of breeding groups was difficult. Conse-
quently, vanStaaden et al. (1994) examined genetic varia-
tion among matrilines, which was likely a level of genetic
structure just above the level at which matings occurs.
Based on postdispersal data from 6 allozyme loci, they
found significant genetic differentiation among matrilines
(table 14.1). This study demonstrated potential for genetic
substructuring in semisocial species that do not exhibit spa-
tially overlapping females in strongly cohesive family
groups.
By far the most complete investigation of gene dynamics
of socially structured kin-groups comes from black-tailed
prairie dogs (Cynomys ludovicianus). Chesser (1983) exam-
ined genetic variation at several levels of population struc-
ture, including coterie breeding groups, using allozyme
alleles. He found significant genetic differentiation among
social groups and among geographically distinct colonies
(table 14.1). Surprisingly, there were greater genetic differ-
ences among social breeding groups than across consider-
able geographic distances. Inbreeding F-statistics (viz., FIX,
where Xcan be L, S,or T) at the level of breeding group,
colony, and regional population were positive and increas-
ing in magnitude. The positive value of FIScontrasts with
other allozyme studies of the same species that found signifi-
cantly or slightly negative values (Foltz and Hoogland 1983;
Daley 1992). So while Chesser’s (1983) study indicated sig-
nificant genetic differences among social groups, it also
raised questions for further research: how could genetic dif-
ferences among social groups match or surpass genetic dif-
ferentiation over geographic ranges, and should inbreeding
F-statistics exhibit a general pattern of increase?
These questions were answered in large part by Sugg
et al. (1996) and Dobson et al. (1997). Sugg et al. (1996)
used published data from Hoogland’s (1995) long-term
study of the behavioral ecology of black-tailed prairie dogs
to estimate gene dynamics, using the breeding-group model
(Chesser 1991a, 1991b; Chesser et al. 1993; Sugg and Ches-
ser 1994). Sugg and Chesser’s (1994) “multiple-paternity”Gene Dynamics and Social Behavior 169Table 14.1 Gene dynamics of selected rodent species, and one species of pika (order Lagomorpha) that were studied with the breeding-group model of Sugg and
Chesser (1994)
Dispersal
Species FLS FIL FIS FIT FST pattern Notes References
Marmota 0.07 0.09 0.07 Post allozyme Schwartz and Armitage
flaviventris 1980
Thomomys 0.07 0.14 0.03 0.28 0.26 Post allozyme Patton and Feder 1981;
bottae Patton and Smith 1990
Spermophilus 0.05 0.40 0.34 Post allozyme, vanStaaden 1994
richardsonii females only
Cynomys 0.23 0.11 0.32 0.40 0.10 mixture allozyme Chesser 1983
ludovicianus
Cynomys 0.16 0.18 0.01 model model Sugg et al. 1996
ludovicianus
Cynomys 0.16 0.18 0.00 model model Dobson et al. 1997,
ludovicianus 2004
Cynomys 0.19 0.23 0.00 Pre pedigree Dobson et al. 1997,
ludovicianus 2004
Cynomys 0.08 0.08 0.00 Post pedigree, Dobson et al. 1997
ludovicianus both sexes
Cynomys 0.03 0.04 0.01 Post pedigree, Dobson et al. 1998a
ludovicianus males only
Cynomys 0.12 0.13 0.01 Post pedigree, Dobson et al. 1998a
ludovicianus females only
Cynomys 0.17 0.21 0.01 mixture allozyme Dobson et al. 1997,
ludovicianus 2004
Cynomys 0.25 0.38 0.03 Pre allozyme Dobson and Chesser
ludovicianus et al. 1998
Cynomys 0.16 0.21 0.02 Post allozyme Dobson and Chesser
ludovicianus et al. 1998
Ochotona 0.30 0.37 0.04 model model; single Dobson and Smith
curzoniae paternity et al. 2000
Ochotona 0.28 0.34 0.04 model model; multiple Dobson and Smith
curzoniae paternity et al. 2000