%0 Journal Article %T A polynomial time algorithm for calculating the probability of a ranked gene tree given a species tree %A Tanja Stadler %A James H. Degnan %J Algorithms for Molecular Biology %D 2012 %I BioMed Central %R 10.1186/1748-7188-7-7 %X In this paper, we provide a polynomial time algorithm to calculate the probability of a ranked gene tree topology for a given species tree, where a ranked tree topology is a tree topology with the internal vertices being ordered. The probability of a gene tree topology can thus be calculated in polynomial time if the number of orderings of the internal vertices is a polynomial number. However, the complexity of calculating the probability of a gene tree topology with an exponential number of rankings for a given species tree remains unknown.Polynomial algorithms for calculating ranked gene tree probabilities may become useful in developing methodology to infer species trees based on a collection of gene trees, leading to a more accurate reconstruction of ancestral species relationships. %U http://www.almob.org/content/7/1/7/abstract