This is because they could not form the cell cluster and algorithmically grouped with a more populous cell cluster due to the small number (only 9, 2, and 0, for the myofibroblasts, PAM+ fibroblast, and MFAP5+ fibroblast cell clusters, respectively; Additional file 2: Table S1) when analyzing solely the scRNA-seq data of the AD rumen. The gene discussed is MFAP5; the disease is Alzheimer disease.