Fine-scale genetic structure and gene dispersal inferences in 10 neotropical tree species.
The extent of gene dispersal is a fundamental factor of the population and evolutionary dynamics of tropical tree species, but directly monitoring seed and pollen movement is a difficult task. However, indirect estimates of historical gene dispersal can be obtained from the fine-scale spatial genetic structure of populations at drift-dispersal equilibrium. Using an approach that is based on the slope of the regression of pairwise kinship coefficients on spatial distance and estimates of the effective population density, we compare indirect gene dispersal estimates of sympatric populations of 10 tropical tree species. We re-analysed 26 data sets consisting of mapped allozyme, SSR (simple sequence repeat), RAPD (random amplified polymorphic DNA) or AFLP (amplified fragment length polymorphism) genotypes from two rainforest sites in French Guiana. Gene dispersal estimates were obtained for at least one marker in each species, although the estimation procedure failed under insufficient marker polymorphism, limited sample size, or inappropriate sampling area. Estimates generally suffered low precision and were affected by assumptions regarding the effective population density. Averaging estimates over data sets, the extent of gene dispersal ranged from 150 m to 1200 m according to species. Smaller gene dispersal estimates were obtained in species with heavy diaspores, which are presumably not well dispersed, and in populations with high local adult density. We suggest that limited seed dispersal could indirectly limit effective pollen dispersal by creating higher local tree densities, thereby increasing the positive correlation between pollen and seed dispersal distances. We discuss the potential and limitations of our indirect estimation procedure and suggest guidelines for future studies.
Hardy
Olivier J
OJ
Université Libre de Bruxelles, Service d'Eco-Ethologie Evolutive, CP 160/12, 50 Av. F. Roosevelt, B-1050 Brussels, Belgium. ohardy@ulb.ac.be
Maggia
Laurent
L
Bandou
Eric
E
Breyne
Peter
P
Caron
Henri
H
Chevallier
Marie-Hélène
MH
Doligez
Agnès
A
Dutech
Cyril
C
Kremer
Antoine
A
Latouche-Hallé
Céline
C
Troispoux
Valérie
V
Veron
Vincent
V
Degen
Bernd
B
D005616:French Guiana; D005819:Genetic Markers; D014644:Genetic Variation; D018895:Microsatellite Repeats; D008957:Models, Genetic; D021141:Nucleic Acid Amplification Techniques; D011110:Polymorphism, Genetic; D019105:Random Amplified Polymorphic DNA Technique; D014197:Trees / Q000235:genetics*; D014329:Tropical Climate
D005819:Genetic Markers