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Reconciling gene trees with a species tree is a fundamental problem to understand the evolution of gene families. Many existing approaches reconcile each gene tree independently. However, it is well-known that the evolution of gene families is interconnected. In this paper, we extend a previous approach to reconcile a set of gene trees with a species tree based on segmental macro-evolutionary events, where segmental duplication events and losses are associated with cost delta and lambda, respectively. We show that the problem is polynomial-time solvable when delta <= lambda (via LCA-mapping), while if delta > lambda the problem is NP-hard, even when lambda = 0 and a single gene tree is given, solving a long standing open problem on the complexity of the reconciliation problem. On the positive side, we give a fixed-parameter algorithm for the problem, where the parameters are delta/lambda and the number d of segmental duplications, of time complexity O(ceil[delta/lambda]^d * n * delta/lambda). Finally, we demonstrate the usefulness of this algorithm on two previously studied real datasets: we first show that our method can be used to confirm or refute hypothetical segmental duplications on a set of 16 eukaryotes, then show how we can detect whole genome duplications in yeast genomes.
@InProceedings{dondi_et_al:LIPIcs.WABI.2018.5,
author = {Dondi, Riccardo and Lafond, Manuel and Scornavacca, Celine},
title = {{Reconciling Multiple Genes Trees via Segmental Duplications and Losses}},
booktitle = {18th International Workshop on Algorithms in Bioinformatics (WABI 2018)},
pages = {5:1--5:16},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-082-8},
ISSN = {1868-8969},
year = {2018},
volume = {113},
editor = {Parida, Laxmi and Ukkonen, Esko},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.WABI.2018.5},
URN = {urn:nbn:de:0030-drops-93079},
doi = {10.4230/LIPIcs.WABI.2018.5},
annote = {Keywords: Gene trees/species tree reconciliation, phylogenetics, computational complexity, fixed-parameter algorithms}
}