Development of functional gene microarrays for microbial community analysis

► Functional gene arrays (FGAs) target key genes for microbial functional processes. ► Summary of currently reported FGAs. ► FGAs have been demonstrated to be a specific, sensitive, and quantitative tool. ► FGAs can be used for rapidly analyzing microbial communities from different habitats. ► Key issues, challenges, and future directions in FGA technology are discussed.