Scalable homology detection with ERAST

Homology search plays a fundamental role in computational biology, enabling the identification of evolutionary relationships and functional similarities among biological sequences. However, current homology search methods, including BLAST, Foldseek and MMseqs2, often struggle to efficiently and accurately process the vast scale of biological databases. Here we introduce ERAST (efficient retrieval-augmented search tool), a solution designed to handle approximately 1 billion biological sequences within the largest vector database to date. ERAST combines large language models and vector database technology to provide both efficient and precise searches for homologous biological sequences. It enhances search quality by integrating preretrieval, retrieval and postretrieval optimization stages, and supports both nucleotide and protein sequences. Through advanced indexing techniques, fine-grained segmentation and metadata integration, ERAST achieves better precision while operating approximately 50 times faster than Foldseek and 50,000 times faster than TM-align. This performance allows ERAST to conduct accurate searches against billions of biological sequences in mere milliseconds. The vector database integrated with ERAST can be accessed at https://ai4s.tencent.com/erast .