Problem
Review the following paper and comment on the following:
a) What is gene co-option? Why/how do you think a gene, regulating an unrelated task (like limb establishment), can be used for a completely new purpose (eyespot regulation)? How might natural selection play a role in the ubiquity of spalt and Dll co-option, seen in multiple butterfly species?
b) Why did the authors notice differences in the levels/types of eyespot loss between J. coenia and V. cardui during spalt deletions in Figure 2? How might the authors want to change their methods/procedures to keep spalt deletions comparable between species? with this analysis, and through what mechanism might the observed decrease in BMP6 be caused?