A scalable and flexible approach for investigating the genomic landscapes of phylogenetic incongruence
2013
Prasad, Arjun B. | Mullikin, James C. | Green, Eric D.
Analyses of DNA sequence datasets have repeatedly revealed inconsistencies in phylogenetic trees derived with different data. This is termed phylogenetic incongruence, and may arise from a methodological failure of the inference process or from biological processes, such as horizontal gene transfer, incomplete lineage sorting, and introgression. To better understand patterns of incongruence, we developed a method (PartFinder) that uses likelihood ratios applied to sliding windows for visualizing tree-support changes across genome-sequence alignments, allowing the comparative examination of complex phylogenetic scenarios among many species. As a pilot, we used PartFinder to investigate incongruence in the Homo-Pan-Gorilla group as well as Platyrrhini using high-quality bacterial artificial chromosome (BAC)-derived sequences as well as assembled whole-genome shotgun sequences. Our simulations verified the sensitivity of PartFinder, and our results were comparable to other studies of the Homo-Pan-Gorilla group. Analyses of the whole-genome alignments reveal significant associations between support for the accepted species relationship and specific characteristics of the genomic regions, such as GC-content, alignment score, exon content, and conservation. Finally, we analyzed sequence data generated for five platyrrhine species, and found incongruence that suggests a polytomy within Cebidae, in particular. Together, these studies demonstrate the utility of PartFinder for investigating the patterns of phylogenetic incongruence.
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