CUSHAW: a CUDA compatible short read aligner to large genomes based on the Burrows-Wheeler transform

May 11th, 2012


Motivation: New high-throughput sequencing technologies have promoted the production of short reads with dramatically low unit cost. The explosive growth of short read datasets poses a challenge to the mapping of short reads to reference genomes, such as the human genome, in terms of alignment quality and execution speed.

Results: We present CUSHAW, a parallelized short read aligner based on the compute unified device architecture (CUDA) parallel programming model. We exploit CUDA-compatible graphics hardware as accelerators to achieve fast speed. Our algorithm employs a quality-aware bounded search approach based on the Burrows- Wheeler transform (BWT) and the Ferragina Manzini (FM)-index to reduce the search space and achieve high alignment quality. Performance evaluation, using simulated as well as real short read datasets, reveals that our algorithm running on one or two graphics processing units (GPUs) achieves significant speedups in terms of execution time, while yielding comparable or even better alignment quality for paired-end alignments compared to three popular BWT-based aligners: Bowtie, BWA and SOAP2. CUSHAW also delivers competitive performance in terms of SNP calling for an E.coli test dataset.


(Y. Liu, B. Schmidt, D. Maskell: “CUSHAW: a CUDA compatible short read aligner to large genomes based on the Burrows-Wheeler transform”, Bioinformatics, 2012. [DOI])

Sequence Homology Search using Fine-Grained Cycle Sharing of Idle GPUs

October 2nd, 2011


In this paper, we propose a fine-grained cycle sharing (FGCS) system capable of exploiting idle graphics processing units (GPUs) for accelerating sequence homology search in local area network environments. Our system exploits short idle periods on GPUs by running small parts of guest programs such that each part can be completed within hundreds of milliseconds. To detect such short idle periods from the pool of registered resources, our system continuously monitors keyboard and mouse activities via event handlers rather than waiting for a screensaver, as is typically deployed in existing systems. Our system also divides guest tasks into small parts according to a performance model that estimates execution times of the parts. This task division strategy minimizes any disruption to the owners of the GPU resources. Experimental results show that our FGCS system running on two non-dedicated GPUs achieves 111-116% of the throughput achieved by a single dedicated GPU. Furthermore, our system provides over two times the throughput of a screensaver-based system. We also show that the idle periods detected by our system constitute half of the system uptime. We believe that the GPUs hidden and often unused in office environments provide a powerful solution to sequence homology search.

(Fumihiko Ino, Yuma Munekawa, and Kenichi Hagihara, “Sequence Homology Search using Fine-Grained Cycle Sharing of Idle GPUs”, accepted for publication in IEEE Transactions on Parallel and Distributed Systems, Sep. 2011. [DOI])

Accelerating Smith-Waterman on Heterogeneous CPU-GPU Systems

June 26th, 2011


This paper describes the approach and the speedup obtained in performing Smith-Waterman database searches on heterogeneous platforms comprising of multi core CPU and multi GPU systems. Most of the advanced and optimized Smith-Waterman algorithm versions have demonstrated remarkable speedup over NCBI BLAST versions, viz., SWPS3 based on x86 SSE2 instructions and CUDASW++ v2.0 CUDA implementation on GPU. This work proposes a hybrid Smith-Waterman algorithm that integrates the state-of-the art CPU and GPU solutions for accelerating Smith-Waterman algorithm in which GPU acts as a co-processor and shares the workload with the CPU enabling us to realize remarkable performance of over 70 GCUPS resulting from simultaneous CPU-GPU execution. In this work, both CPU and GPU are graded equally in performance for Smith-Waterman rather than previous approaches of porting the computationally intensive portions onto the GPUs or a naive multi-core CPU approach.

(J. Singh and I. Aruni: “Accelerating Smith-Waterman on Heterogeneous CPU-GPU Systems”, Proceedings of Bioinformatics and Biomedical Engineering (iCBBE), May 2011. [DOI])

A GPU-accelerated bioinformatics application for large-scale protein networks

February 10th, 2011


Proteins, nucleic acids, and small molecules form a dense network of molecular interactions in a cell. The architecture of molecular networks can reveal important principles of cellular organization and function, similarly to the way that protein structure tells us about the function and organization of a protein. Protein complexes are groups of proteins that interact with each other at the same time and place, forming a single multimolecular machine. Functional modules, in contrast, consist of proteins that participate in a particular cellular process while binding each other at a different time and place.

A protein-protein interaction network is represented as proteins are nodes and interactions between proteins are edges. Protein complexes and functional modules can be identified as highly interconnected subgraphs and computational methods are now inevitable to detect them from protein interaction data. In addition, High-throughput screening techniques such as yeast two-hybrid screening enable identification of detailed protein-protein interactions map in multiple species. As the interaction dataset increases, the scale of interconnected protein networks increases exponentially so that the increasing complexity of network gives computational challenges to analyze the networks. Read the rest of this entry »

Fast and accurate protein substructure searching with simulated annealing and GPUs

September 19th, 2010


Searching a database of protein structures for matches to a query structure, or occurrences of a structural motif, is an important task in structural biology and bioinformatics. While there are many existing methods for structural similarity searching, faster and more accurate approaches are still required, and few current methods are capable of substructure (motif) searching.

We developed an improved heuristic for tableau-based protein structure and substructure searching using simulated annealing, that is as fast or faster, and comparable in accuracy, with some widely used existing methods. Furthermore, we created a parallel implementation on a modern graphics processing unit (GPU). The GPU implementation achieves up to 34 times speedup over the CPU implementation of tableau-based structure search with simulated annealing, making it one of the fastest available methods. To the best of our knowledge, this is the first application of a GPU to the protein structural search problem.

(Stivala, A. and Stuckey, P. and Wirth, A.: “Fast and accurate protein substructure searching with simulated annealing and GPUs”. BMC Bioinformatics, 11:446, Sep. 2010, DOI)

MUMmerGPU 2: Optimizing data intensive GPGPU computations for DNA sequence alignment

August 31st, 2009


MUMmerGPU uses highly-parallel commodity graphics processing units (GPU) to accelerate the data-intensive computation of aligning next generation DNA sequence data to a reference sequence for use in diverse applications such as disease genotyping and personal genomics. MUMmerGPU 2.0 features a new stackless depth-first-search print kernel and is 13× faster than the serial CPU version of the alignment code and nearly 4× faster in total computation time than MUMmerGPU 1.0. We exhaustively examined 128 GPU data layout configurations to improve register footprint and running time and conclude higher occupancy has greater impact than reduced latency. MUMmerGPU is available open-source at

(Trapnell, C, Schatz, MC (2009) Optimizing data intensive GPGPU computations for DNA sequence alignment. Parallel Computing doi:10.1016/j.parco.2009.05.002)

CUDA compatible GPU cards as efficient hardware accelerators for Smith-Waterman sequence alignment

April 2nd, 2008

The Smith-Waterman algorithm has been available for more than 25 years. It is based on a dynamic programming approach that explores all the possible alignments between two biological sequences; as a result it returns the optimal local alignment. Unfortunately, the computational cost is very high, requiring a number of operations proportional to the product of the length of two sequences. This paper by Svetlin Manavski and Giorgio Valle describes SmithWaterman-CUDA, an open-source project to perform fast sequence alignment on the GPU. Although the software performs the optimal Smith-Waterman alignment it is faster than heuristics approaches like FASTA and BLAST. The tests on protein data banks show up to 30x speed up related to reference CPU implementations. (Svetlin A. Manavski, Giorgio Valle, CUDA compatible GPU cards as efficient hardware accelerators for Smith-Waterman sequence alignment, BMC Bioinformatics 2008, 9(Suppl 2):S10 (26 March 2008))

High-throughput sequence alignment using Graphics Processing Units

February 11th, 2008

The recent availability of new, less expensive high-throughput DNA sequencing technologies has yielded a dramatic increase in the volume of sequence data that must be analyzed. by University of Maryland researchers Michael Schatz, Cole Trapnell, Art Delcher, and Amitabh Varshney describes MUMmerGPU, an open-source high-throughput parallel pairwise local sequence alignment program that runs on GPUs. MUMmerGPU uses the new Compute Unified Device Architecture (CUDA) from nVidia to align multiple query sequences against a single reference sequence stored as a suffix tree. By processing the queries in parallel on the graphics card, MUMmerGPU achieves more than a 10-fold speedup over a serial CPU version of the sequence alignment kernel, despite the very low arithmetic intensity of the task. (High-throughput sequence alignment using Graphics Processing Units, Schatz, M.C., Trapnell, C., Delcher, A.L., Varshney, A. (2007), BMC Bioinformatics 8:474.)

Genome Technology Article about GPGPU: “Not Just for Kids Anymore”

September 10th, 2007

This article at Genome Technology gives a brief overview of GPGPU, with a focus on biological information processing using NVIDIA CUDA Technology. The article discusses the results from UIUC’s NAMD / VMD project and neurological simulation company Evolved Machines.

Initial Experiences Porting a Bioinformatics Application to a Graphics Processor

July 1st, 2005

Bioinformatics applications are one of the most compute-demanding applications today. While traditionally these applications are executed on cluster or dedicated parallel systems, this paper by M. Charalambous, P. Trancoso, and A. Stamatikis at the University of Cyprus and FORTH explores the use of an alternative architecture. The authors focus on exploiting the characteristics offered by the graphics processors (GPU) in order to accelerate a bioinformatics application. This paper presents the initial results on porting RAxML, a bioinformatics program for phylogenetic tree inference, to the GPU. (Initial Experiences Porting a Bioinformatics Application to a Graphics Processor. M. Charalambous, P. Trancoso, and A. Stamatakis. Proceedings of the 10th Panhellenic Conference in Informatics (PCI 2005))