Fig. 4.

Transcriptional additive and multiplicative effects in malaria. Examples of transcriptional interaction effects implicating the genes SLC39A8, C3AR1, and PADI3. The case of GSTO1 illustrates the scenario of an interaction effect for a disease phenotype in the absence of a transcriptional interaction. This example illustrates how the effect of the gene is conditional on genotype with only the minor allele homozygote individuals shifting to the resistance zone (transcript abundance >12.0 indicated by horizontal line) when infected, giving rise to an interaction effect for the disease phenotype. Genotypes on the x-axis are labeled to indicate the number of minor alleles and individuals are labeled to indicate their infection status (controls, blue; high parasitemia, red; low parasitemia, orange). The y axis shows normalized expression values.