Lock-free de Bruijn graph

Abstract

De Bruijn graph is one of the most important data structures used in de-novo genome assembly algorithms, especially for NGS data. There is a growing need for parallel data structures and algorithms due to the increasing number of cores in modern computers. The assembly task is an indispensable step in sequencing genomes of new organisms and studying structural genomic changes. In recent years, the dynamic development of next-generation sequencing (NGS) methods raises hopes for making whole-genome sequencing a fast and reliable tool used, for example, in medical diagnostics. However, this is hampered by the slowness and computational requirements of the current processing algorithms, which raises the need to develop more efficient algorithms. One possible approach, still little explored, is the use of quantum computing. We created the lock-free version of the de Bruijn graph, as well as a lock-free algorithm to build such graph from reads. Our algorithm and data structures are developed to use parallel threads of execution and do not use mutexes or other locking mechanisms, instead, we used only compare-and-swap instruction and other atomic operations. It makes our algorithm very fast and efficiently scaling. The presented article depicts the new lock-free de Bruijn graph data structure with a graph build algorithm. We developed a C++ library and tested its performance to depict its high speed and scalability compared to other available tools.