Population history and gene dispersal inferred from spatial genetic structure of a Central African timber tree, Distemonanthus benthamianus (Caesalpinioideae).
African rainforests have undergone major distribution range shifts during the Quaternary, but few studies have investigated their impact on the genetic diversity of plant species and we lack knowledge on the extent of gene flow to predict how plant species can cope with such environmental changes. Analysis of the spatial genetic structure (SGS) of a species is an effective method to determine major directions of the demographic history of its populations and to estimate the extent of gene dispersal. This study characterises the SGS of an African tropical timber tree species, Distemonanthus benthamianus, at various spatial scales in Cameroon and Gabon. Displaying a large continuous distribution in the Lower Guinea domain, this is a model species to detect signs of past population fragmentation and recolonization, and to estimate the extent of gene dispersal. Ten microsatellite loci were used to genotype 295 adult trees sampled from eight populations. Three clearly differentiated gene pools were resolved at this regional scale and could be linked to the biogeographical history of the region, rather than to physical barriers to gene flow. A comparison with the distribution of gene pools observed for two other tree species living in the same region invalidates the basic assumption that all species share the same Quaternary refuges and recolonization pathways. In four populations, significant and similar patterns of SGS were detected. Indirect estimates of gene dispersal distances (sigma) obtained for three populations ranged from 400 to 1200 m, whereas neighbourhood size estimates ranged from 50 to 110.
Debout
G D G
GD
Evolutionary Biology and Ecology, Faculté des Sciences, Université Libre de Bruxelles, Brussels, Belgium. debout_gabriel@yahoo.fr
Doucet
J-L
JL
Hardy
O J
OJ
D002163:Cameroon; D007887:Fabaceae / Q000145:classification / Q000235:genetics*; D005681:Gabon; D017343:Genes, Plant; D014644:Genetic Variation; D010802:Phylogeny; D011153:Population; D014197:Trees / Q000235:genetics*
Mol Ecol. 2004 Apr;13(4):921-35
15012766
Proc Natl Acad Sci U S A. 2007 Dec 18;104(51):20432-6
18077351
Mol Ecol. 2003 Sep;12(9):2483-95
12919486
Biotechniques. 1999 Sep;27(3):500-2, 504-7
10489609
Genetics. 1996 Dec;144(4):2001-14
8978083
Ecol Lett. 2009 Jul;12(7):632-40
19392716
Evolution. 1993 Oct;47(5):1329-1341
28564896
Mol Ecol. 2004 Nov;13(11):3425-35
15488001
Genetics. 2000 Jun;155(2):945-59
10835412
Evolution. 2001 Feb;55(2):260-71
11308084
Mol Ecol. 2006 Feb;15(2):559-71
16448421
Nature. 2000 Jun 22;405(6789):907-13
10879524
Mol Ecol. 2005 Jul;14(8):2611-20
15969739
Genetics. 2003 Apr;163(4):1467-82
12702690
Mol Ecol. 2007 Jun;16(12):2474-87
17561907
Mol Ecol. 2008 Apr;17(8):2041-50
18331246
Heredity (Edinb). 2005 Oct;95(4):255-73
16094300
Evolution. 2003 May;57(5):995-1007
12836818
Genetics. 1996 Nov;144(3):1237-45
8913764
Heredity (Edinb). 2005 Jan;94(1):52-63
15329664
Mol Ecol. 2000 Jul;9(7):831-41
10886647
Mol Ecol. 2009 Nov;18(21):4398-408
19793352
Genet Res. 2007 Dec;89(5-6):491-503
18976539
Mol Phylogenet Evol. 2004 May;31(2):449-61
15062787
Genetics. 2006 Jun;173(2):1033-45
16582447
Genetics. 2003 Aug;164(4):1567-87
12930761
Nucleic Acids Res. 1989 Nov 11;17(21):8543-51
2587212