Figure 4. Schematic of expected expression differences after the
host switch, when compared to differences between control lines using
the example switch Urtica to Ribes. Here, we use the
differences between Host 1 control lines (UdUd ) and either the
Host 2 control lines (RuRu ) on the X axis or the switch from Host
1 to Host 2 (UdRu ) on the y-axis to identify 5 different
categories of expression change: (1) Differences in the gene expression
after the host switch correspond to differences found between the
controls, indicating an adjustment to the new host (green). (2) No
differences in gene expression after the switch despite differences
between the controls, corresponding to the gene expression profiles on
Host 1 (yellow). (3) Differences in gene expression after the switch but
no differences between the controls (blue). (4) differences in gene
expression after the switch that are opposite to differences between
controls (orange) were considered as “mismatches”. (5) Genes that were
not significantly differentially expressed are not shown here. We
predict that 2 hours after a switch the majority of transcriptional
differences will match categories 2 and 3. After 17 hours, larvae should
predominantly show adjustments to the new host (category 1). Expression
changes of category 4 are not expected, and if seen may indicate
transcriptional dysregulation upon switch to the novel host.Ud =Urtica dioica , Ru =Ribes
uva-crispa.