Humbles et al. used the Δdbl GATA mouse which is completely deficient for the eosinophil lineage due to deletion of a high affinity GATA site of the GATA-1 promotor in a mouse model of experimental asthma to demonstrate that eosinophils are not obligatory for allergen-induced lung dysfunction [26]. The gene discussed is QRSL1; the disease is asthma.