The most parsimonious scenario of genome dynamics of euchromatic Cast satDNAs. The multiple expanding lines extending from a single genomic locus represent a sudden burst event in which satDNA spreads on different chromosomes, followed by a second expansion event that leads to further propagation of satDNA. Evidence of such behavior in T. castaneum is shown on top of the figures with three different examples of euchromatic satDNA. The timeline depicts the main events in different colors. Expansion is described as multiple sudden bursts denoted by a sudden increase in intensity and subsequently followed by a slow decrease. The divergence event lasts longer, and its effect is more prominent with time. Elongation has an even later onset with a similarly increasing effect over time. Homogenization is a permanent process affecting all satDNAs; however, the impact of homogenization is the strongest on the longest arrays.
