A. Cloarec et al., Genetic population structure of the German cockroach, Blattella germanica:Absence of geographical variation, ENT EXP APP, 92(3), 1999, pp. 311-319
The genetic structure of 31 populations of the German cockroach, Blattella
germanica (L.), located in two French cities 900 km apart, was estimated by
enzyme gel electrophoresis. A set of 41 loci was analysed. Eight loci (4 E
st, 3 Lap and 1 Got) were polymorphic. Diversity was estimated at different
geographical levels: the overall population, between cities and within a c
ity. Hierarchical F-statistics indicated significant genetic differentiatio
n between all populations and among populations within each city, but no di
fferentiation between cities. F-ST values for populations within each city
and for the overall sample were substantially dissimilar. In addition, a cl
uster analysis did not separate populations according to their geographical
origin but according to the predominance of either of the two alternative
Est-4 alleles. The results of this analysis point to the absence of genetic
differentiation on a large geographical scale: no large-scale geographical
distance effect was detected. However, we evidenced strong genetic substru
cturing on a local scale, within cities.