(D) Stacked bar plot (Marimekko chart) presenting the color-coded relative contribution of choroid plexus cells derived from SPF (green) and GF (yellow) mice. Ranges of p-values are provided for significantly enriched regions per cluster, based on hypergeometric tests. Benjamini-Hochberg correction was applied to correct for multiple testing (*P < 0.05; **P < 0.01). 