As for our phylogenetic analysis, we used PartitionFinder v1.1.0
(Lanfear et al., 2012) to select the best model of nucleotide substitution
and the best partitioning scheme for our 37-taxon dataset
after defining nine potential partitions (3 coding regions 3 codon
positions). The best scheme again combined the data for the three
genes in two partitions (codon positions 1 + 2 and codon position
3), with TrN+I+G identified as the best model of substitution for
both partitions. Thus, for our BEAST runs we used the same parameter
settings for each partition – Substitution Model = TN93; Base
Frequencies = Estimated; Site Heterogeneity Model = Gamma
(with 4 rate categories); Clock Model = Lognormal relaxed clock
(uncorrelated) – and we allowed evolutionary rates and base
frequencies to be unlinked between partitions. We assumed a Speciation: Yule Process model for the Tree Prior (which is generally
appropriate for trees involving sequences from several species),
used a randomly-generated starting tree (subject to the
monophyly constraints noted above), and specified a diffuse
gamma prior distribution (with shape 0.001 and scale 1000) for
the ucld.mean parameter.
As for our phylogenetic analysis, we used PartitionFinder v1.1.0(Lanfear et al., 2012) to select the best model of nucleotide substitutionand the best partitioning scheme for our 37-taxon datasetafter defining nine potential partitions (3 coding regions 3 codonpositions). The best scheme again combined the data for the threegenes in two partitions (codon positions 1 + 2 and codon position3), with TrN+I+G identified as the best model of substitution forboth partitions. Thus, for our BEAST runs we used the same parametersettings for each partition – Substitution Model = TN93; BaseFrequencies = Estimated; Site Heterogeneity Model = Gamma(with 4 rate categories); Clock Model = Lognormal relaxed clock(uncorrelated) – and we allowed evolutionary rates and basefrequencies to be unlinked between partitions. We assumed a Speciation: Yule Process model for the Tree Prior (which is generallyappropriate for trees involving sequences from several species),used a randomly-generated starting tree (subject to themonophyly constraints noted above), and specified a diffusegamma prior distribution (with shape 0.001 and scale 1000) forthe ucld.mean parameter.
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