Abstract
Inferring the functional capabilities of bacteria from metagenome-assembled genomes (MAGs) is becoming a central process in microbiology. Here we show that the completeness of genomes has a significant impact on the recovered functional signal, spanning all domains of metabolic functions. We identify factors that affect this relationship between genome completeness and function fullness, and provide baseline knowledge to guide efforts to correct for this overlooked bias in metagenomic functional inference.