Testing species delimitation in sympatric species complexes: the case of an African tropical tree, Carapa spp. (Meliaceae).
Plant species delimitation within tropical ecosystems is often difficult because of the lack of diagnostic morphological characters that are clearly visible. The development of an integrated approach, which utilizes several different types of markers (both morphological and molecular), would be extremely useful in this context. Here we have addressed species delimitation of sympatric tropical tree species that belong to Carapa spp. (Meliaceae) in Central Africa. We adopted a population genetics approach, sampling numerous individuals from three locations where sympatric Carapa species are known to exist. Comparisons between morphological markers (the presence or absence of characters, leaf-shape traits) and molecular markers (chloroplast sequences, ribosomal internal transcribed spacer region (ITS) sequences, and nuclear microsatellites) demonstrated the following: (i) a strong correlation between morphological and nuclear markers; (ii) despite substantial polymorphism, the inability of chloroplast DNA to discriminate between species, suggesting that cytoplasmic markers represent ineffective DNA barcodes; (iii) lineage sorting effects when using ITS sequences; and (iv) a complex evolutionary history within the genus Carapa, which includes frequent inter-specific gene flow. Our results support the use of a population genetics approach, based on ultra-polymorphic markers, to address species delimitation within complex taxonomic groups.
Service Evolution Biologique et Ecologie, CP160/12, Faculté des Sciences, Université Libre de Bruxelles, 50 Av. F. Roosevelt, 1050 Brussels, Belgium. jduminil@ulb.ac.be
Jérôme
J
Duminil
David
D
Kenfack
Vincenzo
V
Viscosi
Laurent
L
Grumiau
Olivier J
OJ
Hardy
D000704:Analysis of Variance; D001499:Bayes Theorem; D002163:Cameroon; D058893:DNA Barcoding, Taxonomic; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D051456:Gene Flow; D061125:Genes, Chloroplast; D005819:Genetic Markers; D049810:Genetic Speciation; D006239:Haplotypes; D029582:Meliaceae / Q000033:anatomy & histology / Q000145:classification / Q000235:genetics*; D018895:Microsatellite Repeats; D008957:Models, Genetic; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D018515:Plant Leaves / Q000033:anatomy & histology; D011110:Polymorphism, Genetic; D061350:Sympatry
D021903:DNA, Ribosomal Spacer; D005819:Genetic Markers