Figure 1.

Genotype distribution is altered in neonatal litters bred from distinct α₂δ inter-crosses. Expected (magenta lines) and observed (bar graphs) genotypes of neonatal offspring (P0–1) obtained by crossbreeding different α₂δ mutant or single knockout mice (parental genotypes are shown above respective graphs). Symbols indicate either wildtype (+) or mutated (−) α₂δ-1, α₂δ-2, or α₂δ-3 alleles. The absolute number of pups is displayed on the bars and the total amount of analyzed animals is depicted on the upper right side of each graph (confer Table 1 for further information on the number of analyzed litters and mean litter size). While the observed genotype ratio in litters was close to expected values when crossbreeding heterozygous α₂δ-2 mutant mice (A) the frequency of distinct α₂δ single knockout and double knockout mice was below expected ratios in α₂δ-1/-3 (B) α₂δ-1/-2 (C) and α₂δ-2/-3 (D) inter-crosses. Statistics: Chi-square test: (A) ${\chi }_{\left(\text{2}\right)}^{\text{2}}$ = 2.5; (B) left: ${\chi }_{\left(\text{8}\right)}^{\text{2}}$ = 14.6, right: ${\chi }_{\left(\text{5}\right)}^{\text{2}}$ = 18.1; (C) left: ${\chi }_{\left(\text{8}\right)}^{\text{2}}$ = 17.8, middle: ${\chi }_{\left(\text{5}\right)}^{\text{2}}$ = 15.6, right: ${\chi }_{\left(\text{2}\right)}^{\text{2}}$ = 22.6; (D) left: ${\chi }_{\left(\text{8}\right)}^{\text{2}}$ = 24.2, middle: ${\chi }_{\left(\text{5}\right)}^{\text{2}}$ = 11.3, right: ${\chi }_{\left(\text{2}\right)}^{\text{2}}$ = 0.5. Exact p-values are given in the respective graphs. Asterisks in graphs indicate significance levels: *p < 0.05, **p < 0.01, ****p < 0.0001.