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Comparative phylogeography of eight herbs and lianas (Marantaceae) in central African rainforests.

Ley AC, Dauby G, Köhler J, Wypior C, Röser M, Hardy OJ - Front Genet (2014)

Bottom Line: Highest values were found in the hilly areas of Cameroon and Gabon.We hypothesize that retraction of species into one or the other refuge happened by chance depending on the species' distribution range at the time of climate deterioration.The idiosyncratic patterns found in Marantaceae species are similar to those found among tropical tree species, especially in southern LG.

View Article: PubMed Central - PubMed

Affiliation: Institut für Geobotanik und Botanischer Garten, University Halle-Wittenberg Halle (Saale), Germany ; Evolutionary Biology and Ecology, Faculté des Sciences, Université Libre de Bruxelles Brussels, Belgium.

ABSTRACT
Vegetation history in tropical Africa is still to date hardly known and the drivers of population differentiation and speciation processes are little documented. It has often been postulated that population fragmentations following climate changes have played a key role in shaping the geographic distribution patterns of genetic diversity and in driving speciation. Here we analyzed phylogeographic patterns (chloroplast-DNA sequences) within and between eight (sister) species of widespread rainforest herbs and lianas from four genera of Marantaceae (Halopegia, Haumania, Marantochloa, Megaphrynium), searching for concordant patterns across species and concordance with the Pleistocene refuge hypothesis. Using 1146 plastid DNA sequences sampled across African tropical lowland rainforest, particularly in the Lower Guinean (LG) phytogeographic region, we analyzed intra- and interspecific patterns of genetic diversity, endemism and distinctiveness. Intraspecific patterns of haplotype diversity were concordant among most species as well as with the species-level diversity pattern of Marantaceae. Highest values were found in the hilly areas of Cameroon and Gabon. However, the spatial distribution of endemic haplotypes, an indicator for refuge areas in general, was not congruent across species. Each proposed refuge exhibited high values of endemism for one or a few species indicating their potential role as area of retraction for the respective species only. Thus, evolutionary histories seem to be diverse across species. In fact, areas of high diversity might have been both refuge and/or crossing zone of recolonization routes i.e., secondary contact zone. We hypothesize that retraction of species into one or the other refuge happened by chance depending on the species' distribution range at the time of climate deterioration. The idiosyncratic patterns found in Marantaceae species are similar to those found among tropical tree species, especially in southern LG.

No MeSH data available.


Related in: MedlinePlus

Geographic distribution of standardized (i.e., centered and reduced) genetic diversity and endemism for eight Marantaceae species in Lower Guinea for grid cell size 0.75°. Effective number of haplotypes (NAe) (A); mean phylogenetic distance between individuals (v) (B); haplotypic endemism (haplotype range <200 km, End) (C); Genetic distinctiveness of each grid cell (S'i) (D). Distinctiveness above or below average is based on standardized pairwise genetic distance (S'kij computed for each species) among populations where genetic distance is estimated as the number of mutational steps between two individuals drawn from two populations (vij). Species along barplots from left to right are: Halopegia azurea, Haumania danckelmaniana, H. liebrechtsiana, Marantochloa congensis, M. incertifolia, M. monophylla, Megaphrynium macrostachyum and Mega. trichogynum.
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Figure 4: Geographic distribution of standardized (i.e., centered and reduced) genetic diversity and endemism for eight Marantaceae species in Lower Guinea for grid cell size 0.75°. Effective number of haplotypes (NAe) (A); mean phylogenetic distance between individuals (v) (B); haplotypic endemism (haplotype range <200 km, End) (C); Genetic distinctiveness of each grid cell (S'i) (D). Distinctiveness above or below average is based on standardized pairwise genetic distance (S'kij computed for each species) among populations where genetic distance is estimated as the number of mutational steps between two individuals drawn from two populations (vij). Species along barplots from left to right are: Halopegia azurea, Haumania danckelmaniana, H. liebrechtsiana, Marantochloa congensis, M. incertifolia, M. monophylla, Megaphrynium macrostachyum and Mega. trichogynum.

Mentions: Comparing diversity patterns pairwise between species, the Pearson correlation tests revealed congruence between Halopegia azurea, Haumania danckelmaniana, M. incertifolia, M. congensis and M. monophylla (Table 5, Supplementary Table 5) with two main common centers of diversity in Gabon: the western Cristal Mountains area close to Libreville and the northern Chaillu Massif (Figure 4, Supplementary Tables 6, 7). Diversity centers of M. congensis are beside the Cameroonian volcanic line in Cameroon, the Cristal Mountains area, the northern Gabon and only observed in this species: the southern Chaillu Massif of Gabon and the northern part of the RCongo (see Figure 4, Supplementary Tables 6, 7). Furthermore, Mega. macrostachyum and Mega. trichogynum were inter-correlated for NAe. These two species showed many centers of genetic diversity well distributed across Cameroon and Gabon. They shared the center of diversity in the southwest of Gabon with H. liebrechtsiana and M. congensis. Concerning pattern of endemism there is congruence between Marantochloa monophylla and Haumania liebrechtsiana and between M. monophylla and M. incertifolia (the latter only at 0.75°) as well as between Halopegia azurea and M. congensis and between Halopegia azurea and H. danckelmaniana (but the latter only detectable at 1.5° grid because not enough shared cells at 0.75°). Interestingly, there was no congruence in the patterns of haplotypic endemism across species (Supplementary Table 8).


Comparative phylogeography of eight herbs and lianas (Marantaceae) in central African rainforests.

Ley AC, Dauby G, Köhler J, Wypior C, Röser M, Hardy OJ - Front Genet (2014)

Geographic distribution of standardized (i.e., centered and reduced) genetic diversity and endemism for eight Marantaceae species in Lower Guinea for grid cell size 0.75°. Effective number of haplotypes (NAe) (A); mean phylogenetic distance between individuals (v) (B); haplotypic endemism (haplotype range <200 km, End) (C); Genetic distinctiveness of each grid cell (S'i) (D). Distinctiveness above or below average is based on standardized pairwise genetic distance (S'kij computed for each species) among populations where genetic distance is estimated as the number of mutational steps between two individuals drawn from two populations (vij). Species along barplots from left to right are: Halopegia azurea, Haumania danckelmaniana, H. liebrechtsiana, Marantochloa congensis, M. incertifolia, M. monophylla, Megaphrynium macrostachyum and Mega. trichogynum.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4237126&req=5

Figure 4: Geographic distribution of standardized (i.e., centered and reduced) genetic diversity and endemism for eight Marantaceae species in Lower Guinea for grid cell size 0.75°. Effective number of haplotypes (NAe) (A); mean phylogenetic distance between individuals (v) (B); haplotypic endemism (haplotype range <200 km, End) (C); Genetic distinctiveness of each grid cell (S'i) (D). Distinctiveness above or below average is based on standardized pairwise genetic distance (S'kij computed for each species) among populations where genetic distance is estimated as the number of mutational steps between two individuals drawn from two populations (vij). Species along barplots from left to right are: Halopegia azurea, Haumania danckelmaniana, H. liebrechtsiana, Marantochloa congensis, M. incertifolia, M. monophylla, Megaphrynium macrostachyum and Mega. trichogynum.
Mentions: Comparing diversity patterns pairwise between species, the Pearson correlation tests revealed congruence between Halopegia azurea, Haumania danckelmaniana, M. incertifolia, M. congensis and M. monophylla (Table 5, Supplementary Table 5) with two main common centers of diversity in Gabon: the western Cristal Mountains area close to Libreville and the northern Chaillu Massif (Figure 4, Supplementary Tables 6, 7). Diversity centers of M. congensis are beside the Cameroonian volcanic line in Cameroon, the Cristal Mountains area, the northern Gabon and only observed in this species: the southern Chaillu Massif of Gabon and the northern part of the RCongo (see Figure 4, Supplementary Tables 6, 7). Furthermore, Mega. macrostachyum and Mega. trichogynum were inter-correlated for NAe. These two species showed many centers of genetic diversity well distributed across Cameroon and Gabon. They shared the center of diversity in the southwest of Gabon with H. liebrechtsiana and M. congensis. Concerning pattern of endemism there is congruence between Marantochloa monophylla and Haumania liebrechtsiana and between M. monophylla and M. incertifolia (the latter only at 0.75°) as well as between Halopegia azurea and M. congensis and between Halopegia azurea and H. danckelmaniana (but the latter only detectable at 1.5° grid because not enough shared cells at 0.75°). Interestingly, there was no congruence in the patterns of haplotypic endemism across species (Supplementary Table 8).

Bottom Line: Highest values were found in the hilly areas of Cameroon and Gabon.We hypothesize that retraction of species into one or the other refuge happened by chance depending on the species' distribution range at the time of climate deterioration.The idiosyncratic patterns found in Marantaceae species are similar to those found among tropical tree species, especially in southern LG.

View Article: PubMed Central - PubMed

Affiliation: Institut für Geobotanik und Botanischer Garten, University Halle-Wittenberg Halle (Saale), Germany ; Evolutionary Biology and Ecology, Faculté des Sciences, Université Libre de Bruxelles Brussels, Belgium.

ABSTRACT
Vegetation history in tropical Africa is still to date hardly known and the drivers of population differentiation and speciation processes are little documented. It has often been postulated that population fragmentations following climate changes have played a key role in shaping the geographic distribution patterns of genetic diversity and in driving speciation. Here we analyzed phylogeographic patterns (chloroplast-DNA sequences) within and between eight (sister) species of widespread rainforest herbs and lianas from four genera of Marantaceae (Halopegia, Haumania, Marantochloa, Megaphrynium), searching for concordant patterns across species and concordance with the Pleistocene refuge hypothesis. Using 1146 plastid DNA sequences sampled across African tropical lowland rainforest, particularly in the Lower Guinean (LG) phytogeographic region, we analyzed intra- and interspecific patterns of genetic diversity, endemism and distinctiveness. Intraspecific patterns of haplotype diversity were concordant among most species as well as with the species-level diversity pattern of Marantaceae. Highest values were found in the hilly areas of Cameroon and Gabon. However, the spatial distribution of endemic haplotypes, an indicator for refuge areas in general, was not congruent across species. Each proposed refuge exhibited high values of endemism for one or a few species indicating their potential role as area of retraction for the respective species only. Thus, evolutionary histories seem to be diverse across species. In fact, areas of high diversity might have been both refuge and/or crossing zone of recolonization routes i.e., secondary contact zone. We hypothesize that retraction of species into one or the other refuge happened by chance depending on the species' distribution range at the time of climate deterioration. The idiosyncratic patterns found in Marantaceae species are similar to those found among tropical tree species, especially in southern LG.

No MeSH data available.


Related in: MedlinePlus