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Comparative allozyme and microsatellite population structure in a narrow endemic plant species, Centaurea corymbosa Pourret (Asteraceae)
Author(s) -
Freville H.,
Justy F.,
Olivieri I.
Publication year - 2001
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1046/j.1365-294x.2001.01249.x
Subject(s) - biology , microsatellite , gene flow , isolation by distance , asteraceae , population , locus (genetics) , genetic structure , genetic variation , biological dispersal , evolutionary biology , genetics , botany , gene , allele , demography , sociology
Centaurea corymbosa Pourret (Asteraceae) is a narrow endemic species known only from six populations located in a 3‐km 2 area in the south of France. Earlier field experiments have suggested that pollen and seed dispersal were highly restricted within and among populations. Consistent with the field results, populations were highly differentiated for five allozyme loci and among‐population variation fitted an isolation‐by‐distance model. In the present study, we investigated the genetic structure of C. corymbosa using six microsatellite loci. As with allozymes, microsatellites revealed no within‐population structure and a large differentiation among populations. However, allozyme loci were less powerful than microsatellites in detecting the extent of gene flow assessed by assignment tests. The patterns of structuration greatly varied among loci for both types of marker; we suggest that differences in single‐locus pattern could mainly be an effect of stochastic variation for allozymes and an effect of variation in mutation rate for microsatellites. In contrast to the multilocus results, the two most polymorphic microsatellite loci did not show any isolation‐by‐distance pattern. Our results suggest that highly variable loci might not always be the best suited markers to quantify levels of gene flow among populations.