bab
finds all most parsimonious trees.
Details
This implementation is very slow and depending on the data may take very
long time. In the worst case all \((2n-5)!! = 1 \times 3 \times 5
\times \ldots \times (2n-5)\) possible
trees have to be examined, where n is the number of species / tips. For ten
species there are already 2027025 tip-labelled unrooted trees. It only uses
some basic strategies to find a lower and upper bounds similar to penny from
phylip. bab
uses a very basic heuristic approach of MinMax Squeeze
(Holland et al. 2005) to improve the lower bound. bab
might return multifurcating trees. These multifurcations could be
resolved in all ways.
On the positive side bab
is not like many other implementations
restricted to binary or nucleotide data.
References
Hendy, M.D. and Penny D. (1982) Branch and bound algorithms to determine minimal evolutionary trees. Math. Biosc. 59, 277-290
Holland, B.R., Huber, K.T. Penny, D. and Moulton, V. (2005) The MinMax Squeeze: Guaranteeing a Minimal Tree for Population Data, Molecular Biology and Evolution, 22, 235–242
White, W.T. and Holland, B.R. (2011) Faster exact maximum parsimony search with XMP. Bioinformatics, 27(10),1359–1367
Author
Klaus Schliep klaus.schliep@gmail.com based on work on Liam Revell
Examples
data(yeast)
dfactorial(11)
#> [1] 10395
# choose only the first two genes
gene12 <- yeast[, 1:3158]
trees <- bab(gene12)
#> Compute starting tree
#> lower bound: 2625
#> upper bound: 3487
#> Search Baumraum (tree space)
#>
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