2.17 Content of transposon related to opsin gene
To examine if transposons flanking the opsin genes contribute to gene conversion, we used a 100 kb sliding window along the chromosome to statistically determine the gene number and transposon number per window (Perl script). We plotted gene numbers and transposon numbers per window and drew a distribution of gene/transposon (R script). A one-sample Poisson test was used to validate significant differences in the transposon numbers of the opsin window and its flanking window, and aP value <0.01 was regarded as the transposon hotspot region.