An efficient digital circuit for implementing Sequence Alignment algorithm in an extended processor

The problem of sequence alignment (Edit Distance) between a pair of strings has been well studied in the field of computing algorithms. The classic dynamic programming-based algorithm, Needleman-Wunsch (O(n²)), has been widely used in practice, especially by biologists to find similarities between gene sequences. Any optimization in the implementation of this algorithm will have a significant practical impact on biological research. However, within the past several decades, not much has been done in improving the runtime of the algorithm in real implementations. Although algorithms based on systolic processor arrays and FPGAs were presented earlier to create custom hardware to aid in speed-up, their usage has been very limited due to their inherent synchronous design complexity and scalability issues. In view of this, we propose an efficient hardware implementation of the Sequence Alignment algorithm. We provide a simple and efficient asynchronous sequential design which can be readily implemented as an instruction in an extensible processor. Experimental results show that our circuit implementation can achieve a speed-up of 3.77X on average compared with the software counterpart, meanwhile reducing the area cost.