Limits...
Complex phylogeographic history of central African forest elephants and its implications for taxonomy.

Johnson MB, Clifford SL, Goossens B, Nyakaana S, Curran B, White LJ, Wickings EJ, Bruford MW - BMC Evol. Biol. (2007)

Bottom Line: We find that central African forest elephant populations fall into at least two lineages and that west African elephants (both forest and savannah) share their mitochondrial history almost exclusively with central African forest elephants.We also find that central African forest populations show lower genetic diversity than those in savannahs, and infer a recent population expansion.The demographic history of African elephants seems more complex, with a combination of multiple refugial mitochondrial lineages and recurrent hybridization among them rendering a simple forest/savannah elephant split inapplicable to modern African elephant populations.

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Affiliation: Centre International de Recherches M├ędicales de Franceville (CIRMF), BP 769, Franceville, Gabon. johnson-bawem@cf.ac.uk

ABSTRACT

Background: Previous phylogenetic analyses of African elephants have included limited numbers of forest elephant samples. A large-scale assessment of mitochondrial DNA diversity in forest elephant populations here reveals a more complex evolutionary history in African elephants as a whole than two-taxon models assume.

Results: We analysed hypervariable region 1 of the mitochondrial control region for 71 new central African forest elephants and the mitochondrial cytochrome b gene from 28 new samples and compare these sequences to other African elephant data. We find that central African forest elephant populations fall into at least two lineages and that west African elephants (both forest and savannah) share their mitochondrial history almost exclusively with central African forest elephants. We also find that central African forest populations show lower genetic diversity than those in savannahs, and infer a recent population expansion.

Conclusion: Our data do not support the separation of African elephants into two evolutionary lineages. The demographic history of African elephants seems more complex, with a combination of multiple refugial mitochondrial lineages and recurrent hybridization among them rendering a simple forest/savannah elephant split inapplicable to modern African elephant populations.

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Mismatch distribution of the HVR1 haplogroups of African elephants.
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Figure 5: Mismatch distribution of the HVR1 haplogroups of African elephants.

Mentions: When HVR1 sequences from forest and savannah elephants were examined separately, Fu's Fs was -14.2954 (P = 0.0021) and -24.4427 (P < 0.0001), respectively. Although significant values can indicate historical population expansion, the multimodal pattern (Figure 4) for the forest elephant groups suggests that these populations encompass several subgroups as indicated in the networks. When we examined each haplogroup separately for signatures of demographic change (Table 3), a smooth and predominantly unimodal pattern was observed for HVR1 Haplogroup I, indicating a recent demographic expansion (Figure 5), while HVR1 Haplogroups II, III and IV were more complex, including the presence of some divergent haplotypes.


Complex phylogeographic history of central African forest elephants and its implications for taxonomy.

Johnson MB, Clifford SL, Goossens B, Nyakaana S, Curran B, White LJ, Wickings EJ, Bruford MW - BMC Evol. Biol. (2007)

Mismatch distribution of the HVR1 haplogroups of African elephants.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2262091&req=5

Figure 5: Mismatch distribution of the HVR1 haplogroups of African elephants.
Mentions: When HVR1 sequences from forest and savannah elephants were examined separately, Fu's Fs was -14.2954 (P = 0.0021) and -24.4427 (P < 0.0001), respectively. Although significant values can indicate historical population expansion, the multimodal pattern (Figure 4) for the forest elephant groups suggests that these populations encompass several subgroups as indicated in the networks. When we examined each haplogroup separately for signatures of demographic change (Table 3), a smooth and predominantly unimodal pattern was observed for HVR1 Haplogroup I, indicating a recent demographic expansion (Figure 5), while HVR1 Haplogroups II, III and IV were more complex, including the presence of some divergent haplotypes.

Bottom Line: We find that central African forest elephant populations fall into at least two lineages and that west African elephants (both forest and savannah) share their mitochondrial history almost exclusively with central African forest elephants.We also find that central African forest populations show lower genetic diversity than those in savannahs, and infer a recent population expansion.The demographic history of African elephants seems more complex, with a combination of multiple refugial mitochondrial lineages and recurrent hybridization among them rendering a simple forest/savannah elephant split inapplicable to modern African elephant populations.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre International de Recherches M├ędicales de Franceville (CIRMF), BP 769, Franceville, Gabon. johnson-bawem@cf.ac.uk

ABSTRACT

Background: Previous phylogenetic analyses of African elephants have included limited numbers of forest elephant samples. A large-scale assessment of mitochondrial DNA diversity in forest elephant populations here reveals a more complex evolutionary history in African elephants as a whole than two-taxon models assume.

Results: We analysed hypervariable region 1 of the mitochondrial control region for 71 new central African forest elephants and the mitochondrial cytochrome b gene from 28 new samples and compare these sequences to other African elephant data. We find that central African forest elephant populations fall into at least two lineages and that west African elephants (both forest and savannah) share their mitochondrial history almost exclusively with central African forest elephants. We also find that central African forest populations show lower genetic diversity than those in savannahs, and infer a recent population expansion.

Conclusion: Our data do not support the separation of African elephants into two evolutionary lineages. The demographic history of African elephants seems more complex, with a combination of multiple refugial mitochondrial lineages and recurrent hybridization among them rendering a simple forest/savannah elephant split inapplicable to modern African elephant populations.

Show MeSH
Related in: MedlinePlus