FIG 4.

Identification of a Multitrait QTL on Chr9. Each of the individual F2 mice were genotyped using MiniMuga and QTL mapping conducted by testing the strength of association between each F2 mouse’s phenotype and their genotypes at each marker. (A) A quantitative multitrait locus with major effect was identified on Chr9 (74.9–124 Mb), which affected mortality, weight loss, lung congestion, lung function, and peripheral hematology. CC011/Unc has a C57BL/6/PWK haplotype and CC074/Unc has an A/J/PWK haplotype in this QTL region. (B) Expression levels of Ccr9, Cxcr6, Xcr1, Lztfl1, Fyco1, and Slc6a20a/b of SARS-CoV-2 MA10-infected CC011 and CC074 mice at 4 dpi, determined by quantitative RT-PCR, normalized to Gapdh (female 10- to 12-week-old mice were infected with 1 × 10⁴ PFU SARS-CoV-2 MA10; CC011: n = 5, CC074: n = 5). Data were analyzed using Mann-Whitney test; *, P < 0.05; **, P < 0.005.