## Computational grand challenges in assembling the tree of life: Problems & solutions (2005)

Venue: | THE IEEE AND ACM SUPERCOMPUTING CONFERENCE 2005 (SC2005) TUTORIAL |

Citations: | 7 - 0 self |

### BibTeX

@INPROCEEDINGS{Bader05computationalgrand,

author = {David A. Bader and Usman Roshan and Alexandros Stamatakis},

title = {Computational grand challenges in assembling the tree of life: Problems & solutions},

booktitle = {THE IEEE AND ACM SUPERCOMPUTING CONFERENCE 2005 (SC2005) TUTORIAL},

year = {2005},

publisher = {}

}

### OpenURL

### Abstract

The computation of ever larger as well as more accurate phylogenetic (evolutionary) trees with the ultimate goal to compute the tree of life represents one of the grand challenges in High Performance Computing (HPC) Bioinformatics. Unfortunately, the size of trees which can be computed in reasonable time based on elaborate evolutionary models is limited by the severe computational cost inherent to these methods. There exist two orthogonal research directions to overcome this challenging computational burden: First, the development of novel, faster, and more accurate heuristic algorithms and second, the application of high performance computing techniques. The goal of this chapter is to provide a comprehensive introduction to the field of computational evolutionary biology to an audience with computing background, interested in participating in research and/or commercial applications of this field. Moreover, we will cover leading-edge technical and algorithmic developments in the field and discuss open problems and potential solutions.

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Citation Context ...derstanding evolution. Problems related to phylogeny reconstruction are widely studied. Most have been proven or are believed to be NP-hard problems that can take years to solve on realistic datasets =-=[5, 6]-=-. Many biologists throughout the world compute phylogenies involving weeks or years of computation without necessarily finding global optima. Certainly more such computational analyses will be needed ... |

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Citation Context ...e is that it does not constrain the character states of the input and can use real molecular data and also characters reduced from gene-order data such as Maximum Parsimony on Binary Encodings (MPBE) =-=[25]-=-. The University of New Mexico operates Los Lobos, the NSF / Alliance 512processor Linux supercluster. This platform is a cluster of 256 IBM Netfinity 4500R nodes, each with dual 733 MHz Intel Xeon Pe... |

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Citation Context ...derstanding evolution. Problems related to phylogeny reconstruction are widely studied. Most have been proven or are believed to be NP-hard problems that can take years to solve on realistic datasets =-=[5, 6]-=-. Many biologists throughout the world compute phylogenies involving weeks or years of computation without necessarily finding global optima. Certainly more such computational analyses will be needed ... |

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Citation Context ... within less than 24 hours. Therefore, large-scale phylogenetic analyses with ML are becoming more common recently [55]. The computation of the ML tree has recently been demonstrated to be NPcomplete =-=[56]-=-. The problem of finding the optimal ML tree is particularly difficult due to the immense amount of alternative tree topologies which have to be evaluated and the high computational cost—in terms of f... |

42 |
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Citation Context ...to reconstruct sequence-based phylogeny. The most popular phylogeny software suites that contain parsimony methods are PAUP* by Swofford [20], PHYLIP by Felsenstein [21], and TNT and NONA by Goloboff =-=[22, 23]-=-. We have developed a freely-available sharedmemory code for computing MP, that is part of our software suite, GRAPPA (Genome Rearrangement Analysis through Parsimony and other Phylogenetic Algorithms... |

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Citation Context ...e a much smaller set of most promising topologies and choose the best one examined. One advantage of B&B is that it provides instance-specific lower bounds, showing how close a solution is to optimal =-=[15]-=-. The phylogeny reconstruction problem with maximum parsimony (MP) is defined as follows. The input is a set of c characters and a set of taxa represented as length-c sequences of values (one for each... |

36 |
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Citation Context ...ignment along with its sequence length and source. 1. 101 RNA, 1858 bp [44], obtained from Alexandros Stamatakis 2. 150 RNA, 1269 bp [44], obtained from Alexandros Stamatakis 3. 150 ssu rRNA, 3188 bp =-=[45]-=-, obtained from Alexandros Stamatakis 4. 193 ssu rRNA [46], obtained from Alexandros Stamatakis 5. 200 ssu rRNA, 3270 bp [45], obtained from Alexandros Stamatakis 6. 218 ssu rRNA, 4182 bp [47], obtain... |

34 | Rec-I-DCM3: A Fast Algorithmic Technique for Reconstructing Large Phylogenetic Trees
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Citation Context .... This technique will also be available under the CIPRES project software distribution. Usman’s publications can be found at his web page at http://www.cs.njit.edu/usman. Representative Publications: =-=[37, 35, 36, 30, 31, 28, 32, 17, 37]-=-. Alexandros Stamatakis received his Ph.D. in Computer Science from the Technical University of Munich (Germany) in October 2004. He currently works as postdoctoral researcher at the Institute of Comp... |

32 |
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Citation Context ...RNA, 1858 bp [44], obtained from Alexandros Stamatakis 2. 150 RNA, 1269 bp [44], obtained from Alexandros Stamatakis 3. 150 ssu rRNA, 3188 bp [45], obtained from Alexandros Stamatakis 4. 193 ssu rRNA =-=[46]-=-, obtained from Alexandros Stamatakis 5. 200 ssu rRNA, 3270 bp [45], obtained from Alexandros Stamatakis 6. 218 ssu rRNA, 4182 bp [47], obtained from Alexandros Stamatakis 7. 250 ssu rRNA [45], obtain... |

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Citation Context ... Mexico’s 512-processor NSF Linux SMP supercluster, and achieved a one-million-fold speedup over prior methods—a speed-up that he has since increased to over one billion. Representative Publications: =-=[1,7,8,11,12,14,13,9,15,16,6,2,3,4,5,18,20,19,23,24,26,27,29,25, 33, 34, 40, 48, 49, 50]-=-. Bader has co-presented several tutorials at prior SC meetings: at SC1999 (high-performance computing in the Alliance), at SC2000 (an updated tutorial with the same focus and a second tutorial on par... |

29 | Industrial Applications of High-Performance Computing for Phylogeny Reconstruction
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(Show Context)
Citation Context ...medicine (as well as linguistics). Naturally, scientists are interested in phylogenies for the sake of knowledge, but such analyses also have many uses in applied research and in the commercial arena =-=[12]-=-. Existing phylogenetic reconstruction techniques suffer from serious problems of running time (or, when fast, of accuracy). The problem is particularly serious for large data sets: even though data s... |

29 | Parallel implementation and performance of fastDNAml - a program for maximum likelihood phylogenetic inference
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(Show Context)
Citation Context ...achine alignments, i.e., those created solely by a computer program with no human intervention. Below we list the size of each alignment along with its sequence length and source. 1. 101 RNA, 1858 bp =-=[44]-=-, obtained from Alexandros Stamatakis 2. 150 RNA, 1269 bp [44], obtained from Alexandros Stamatakis 3. 150 ssu rRNA, 3188 bp [45], obtained from Alexandros Stamatakis 4. 193 ssu rRNA [46], obtained fr... |

28 |
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Citation Context ...rictions on the changes between adjacent nodes) are often classified into Fitch, Wagner, Dollo, and Generalized (Sankoff) Parsimony [7]. In this example, we use the simplest criteria, Fitch parsimony =-=[16]-=-, which imposes no constraints on permissible character state changes. The optimization techniques we discuss are similar across all of these types of parsimony. Given a topology with leaf labels, we ... |

28 |
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(Show Context)
Citation Context ...rison to RAxML, IQPNNI is both slower and less accurate [80].sSimulated Annealing Approaches: The first application of simulated annealing techniques to ML tree searches was proposed by Salter et al. =-=[81]-=- (the technique has previously been applied to MP phylogenetic tree searches by D. Barker [82]). However, the respective program SSA has not become very popular due to the limited availability of nucl... |

27 |
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Citation Context ... and the increasing use of parallel computers allow for inference of huge phylogenies within less than 24 hours. Therefore, large-scale phylogenetic analyses with ML are becoming more common recently =-=[55]-=-. The computation of the ML tree has recently been demonstrated to be NPcomplete [56]. The problem of finding the optimal ML tree is particularly difficult due to the immense amount of alternative tre... |

27 | Initial experiences porting a bioinformatics application to a graphics processor
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Citation Context ...ouble require more memory space. Thus, the choice of double precision appears to represent a reasonable trade-off. A porting of RAxML from double to float for the purposes of the GPGPU implementation =-=[97]-=- (see Section 3.4) did not yield better results in terms of execution times. Number of Likelihood Scalings 2.5e+06 2e+06 1.5e+06 1e+06 500000 "likelihood_scalings" 0 0 500 1000 1500 2000 2500 Number o... |

26 |
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Citation Context ... floating point operations—of each tree evaluation per se. To date, the main focus of researchers has been on improving the search algorithms (RAxML [57], PHYML [58], GAML [59], IQPNNI [46], MetaPIGA =-=[60]-=-, Treefinder [61]) and on accelerating the likelihood function via algorithmic means by detecting and re-using previously computed values [62, 63]. Due to the algorithmic progress which has been achie... |