Number of paralogs and age of the loci with variable ITRs. (a) Comparison between the number of paralogs of the 210 loci with variable ITRs and the remaining 1,798 nearly identical loci. The former are enriched in large groups of paralogs. (b) The same trend is observed when only the paralogs directly hosting ITR-containing exons are compared to the rest. (c) Sequence identity between all pairs of SDs (25,914), pairs of SDs with variable ITRs (496), and pairs of SDs with the longest version of each ITR (168). The last two are enriched in highly identical SDs. (d) Overlap between SDs and human CNVs. Both SDs with variable ITRs and SDs with longer versions of each ITR tend to overlap with human CNVs. *P-value < 0.01 (chi-squared test between the corresponding fraction of SDs and all SDs in that bin of sequence identity).