Historical and contemporary mating patterns in remnant populations of the forest tree Fraxinus excelsior L.
Evolution
; 59(5): 979-90, 2005 May.
Article
in En
| MEDLINE
| ID: mdl-16136798
ABSTRACT
Genetic variation at microsatellite markers was used to quantify genetic structure and mating behavior in a severely fragmented population of the wind-pollinated, wind-dispersed temperate tree Fraxinus excelsior in a deforested catchment in Scotland. Remnants maintain high levels of genetic diversity, comparable with those reported for continuous populations in southeastern Europe, and show low interpopulation differentiation (E = 0.080), indicating that historical gene exchange has not been limited (Nm = 3.48). We estimated from seeds collected from all trees producing fruits in three of five remnants that F. excelsior is predominantly outcrossing (t(m) = 0.971 +/- 0.028). Use of a neighborhood model approach to describe the relative contribution of local and long-distance pollen dispersal indicates that pollen gene flow into each of the three remnants is extensive (46-95%) and pollen dispersal has two components. The first is very localized and restricted to tens of meters around the mother trees. The second is a long-distance component with dispersal occurring over several kilometers. Effective dispersal distances, accounting for the distance and directionality to mother trees of sampled pollen donors, average 328 m and are greater than values reported for a continuous population. These results suggest that the opening of the landscape facilitates airborne pollen movement and may alleviate the expected detrimental genetic effects of fragmentation.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Genetic Variation
/
Fraxinus
/
Biological Evolution
/
Genetics, Population
Type of study:
Prognostic_studies
Country/Region as subject:
Europa
Language:
En
Journal:
Evolution
Year:
2005
Type:
Article
Affiliation country:
United kingdom