Consequences of unequal population size, asymmetric gene flow and sex-biased dispersal on population structure in brook charr (Salvelinus fontinalis)

Unravelling relationships between dispersal and population structure requires considering the impacts of assumption violations of indirect gene flow models in a given system. We combined temporal, individual and coalescent‐based analyses of microsatellite DNA variation to explore the general hypothe...

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Bibliographic Details
Published in:Molecular ecology 2004-01, Vol.13 (1), p.67-80
Main Authors: Fraser, Dylan J., Lippé, Catherine, Bernatchez, Louis
Format: Article
Language:English
Subjects:
Animals
assignment test
Body Weights and Measures
Cluster Analysis
dispersal
Female
Fresh Water
Freshwater
Gene Frequency
Genetic Variation
Genetics, Population
Homing Behavior - physiology
local adaptation
Male
metapopulation
Microsatellite Repeats - genetics
Models, Genetic
Movement - physiology
philopatry
Population Density
Quebec
recolonization
Sex Factors
social behaviour
Trout - genetics
Trout - physiology
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Summary:Unravelling relationships between dispersal and population structure requires considering the impacts of assumption violations of indirect gene flow models in a given system. We combined temporal, individual and coalescent‐based analyses of microsatellite DNA variation to explore the general hypothesis that unequal effective population size (Ne), asymmetric gene flow (m) and nonrandom (sex‐biased) individual dispersal had an important effect on spatiotemporal population structuring in lake‐dwelling brook charr (Salvelinus fontinalis). This integrative examination shed light on the dichotomous structuring observed between an outlet and three tributary‐spawning populations and their potential for adaptive divergence. It revealed further that finer tributary population structuring incongruent with drainage structure has been shaped by asymmetric m from one population with a large Ne towards two populations of smaller Ne. Gene flow among the tributaries was also mediated mainly by male‐biased dispersal. However, longer distance dispersal from tributaries to the outflow was female‐biased. Spatially dependent sex‐biased dispersal may have contributed therefore to gene flow at different levels of population structuring. Our results demonstrate how dispersal and population structure may interrelate to produce spatial variation in intraspecific diversity, and are therefore relevant for conservation programmes seeking to define conservation units or predict recolonization rates of extirpated populations.
ISSN:0962-1083
1365-294X
DOI:10.1046/j.1365-294X.2003.02038.x