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An alternative source of time constraints in teleostean phylogeny by evaluating a …

Home » Biology Articles » Biogeography » Mitogenomic evaluation of the historical biogeography of cichlids toward reliable dating of teleostean divergences » Figures

- Mitogenomic evaluation of the historical biogeography of cichlids toward reliable dating of teleostean divergences

mcith_1471-2148-8-215-1.jpg Figure 1 A Bayesian tree based on mitogenomic DNA sequences. This is a 50% majority rule consensus tree among 10,000 pooled trees from two independent Bayesian MCMC runs. The data set comprises aligned gap-free nucleotide sequences of 10,034-bp length from 54 taxa, which included 4,887 variable sites and 3,936 parsimony-informative sites. Partitioned Bayesian analyses were conducted using the GTR + I + Γ model and with all model parameters variable and unlinked across partitions. The numerals at internal nodes or branches indicate Bayesian posterior probabilities (left) and maximum likelihood bootstrap probability values (right) from 1000 replicates, respectively (shown as percentage for values above 50%).

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mcith_1471-2148-8-215-2.jpg Figure 2 A posterior distribution of divergence times with 95% credibility intervals (shaded rectangles) was obtained using mitogenomic DNA sequences (10,034 sites). Two sharks (Scyliorhinus canicula and Mustelus manazo) were used as an outgroup (not shown). The multidistribute program [41] was used to estimate divergence times assuming the tree topology shown in Fig. 1. Letters indicate nodes at which maximum and/or minimum time constraints were set (see Table 2 for details of the individual constraints). Paleogeographical maps at 148 MYA, 120 MYA, 95 MYA, and 85 MYA [50] are shown. Dark-gray areas on the maps represent those being fragmented within Gondwanaland at those times.

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mcith_1471-2148-8-215-3.jpg Figure 3 Comparison of paleontological and molecular estimates of divergence times. Minimum estimates of divergence times deducible from fossil records (see Table 2) were plotted as closed circles against molecularly estimated divergence times (mean values for the divergence times shown in Fig. 2). Closed triangles show plots of the timing of continental breakups against the molecular time estimates of cichlid divergences between the corresponding continents (data taken from Fig. 2). The timings used for complete continental breakups are 112 MYA for (Africa + South America) vs. (Madagascar + Indo/Sri Lanka), 100 MYA for Africa vs. South America, and 85 MYA for Madagascar vs. Indo/Sri Lanka [50-52]. The solid line indicates a 1:1 relationship between paleontological and molecular time estimates.

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mcith_1471-2148-8-215-4.jpg Figure 4 Divergence times estimated from the partitioned Bayesian analysis using both paleontological time constraints (Table 2) and biogeographical assumptions for the divergences of continental cichlid groups. The added time constraints on cichlid divergences are as follows: 112 MYA (lower) and 145 MYA (upper) for (Africa + South America) vs. (Madagascar + Indo/Sri Lanka); 100 MYA (lower) and 120 MYA (upper) for Africa vs. South America; and 85 MYA (lower) and 95 MYA (upper) for Madagascar vs. Indo/Sri Lanka [50-52]. See Fig. 2 legend for other details.

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