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Population genetic structure of North American thinhorn sheep ( Ovis dalli )
Author(s) -
WORLEY K.,
STROBECK C.,
ARTHUR S.,
CAREY J.,
SCHWANTJE H.,
VEITCH A.,
COLTMAN D. W.
Publication year - 2004
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 - 10.1111/j.1365-294x.2004.02248.x
Subject(s) - biology , biological dispersal , subspecies , range (aeronautics) , ovis , ecology , population , genetic structure , isolation by distance , genetic diversity , genetic variation , zoology , evolutionary biology , demography , genetics , materials science , sociology , gene , composite material
The thinhorn sheep ( Ovis dalli ssp.) provides a rare example of a North American large mammal that occupies most of its native range and maintains close to ancestral population size. There are currently two recognized subspecies, Dall's sheep ( O. d. dalli ) and Stone's sheep ( O. d. stonei ), the validity of which remains uncertain. We investigated the spatial genetic structure of thinhorn sheep populations representing both subspecies by genotyping individuals ( n = 919) from across the species range at 12 variable microsatellite loci. We found high levels of genetic diversity within ( H E = 0.722) and significant genetic structure among the 24 sampled areas ( F ST = 0.160). Genetic distance measures and Bayesian clustering analyses revealed the presence of at least eight subpopulations that are delineated by mountain range topology. A strong overall pattern of isolation‐by‐distance is evident across the sampling range ( r = 0.75, P < 0.001) suggesting limited dispersal and extensive philopatry. Partial Mantel tests of this relationship showed mountain range distinctions represent significant barriers to gene flow ( P = 0.0001), supporting the Bayesian analyses. Genetic structure was more strongly pronounced in southern Yukon and Alaska than elsewhere. We also show evidence for genetic differences between the two currently recognized thinhorn subspecies.