The brown rat is a creature often overlooked, yet one of science’s most important models for studying human disease. Now, researchers led by UTHealth Houston have assembled the most complete genetic profile of the brown rat to date, a breakthrough that could transform how scientists investigate conditions like heart disease, kidney disease, high blood pressure, and stroke. Using long-read sequencing, the researchers created the first telomere-to-telomere assembly of the rat genome, an unbroken description of all 22 pairs of chromosomes. To capture genetic diversity, the team assembled eight reference-quality rat genomes, creating a pangenome that adds 7% more sequence to the species’ genetic map. For example, Doris points to a protease gene involved in digestion:The new brown rat genome assembly gives scientists a complete genetic fingerprint, filling in missing pieces that once made disease research difficult.