Data from: Thoracic underreplication in Drosophila species estimates a minimum genome size and the dynamics of added DNA

Many cells in the thorax of Drosophila were found to stall during
replication, a phenomenon known as underreplication. Unlike
underreplication in nuclei of salivary and follicle cells, this stall
occurs with less than one complete round of replication. This stall point
allows precise estimations of early-replicating euchromatin and
late-replicating heterochromatin regions, providing a powerful tool to
investigate the dynamics of structural change across the genome. We
measure underreplication in 132 species across the Drosophila genus and
leverage this data to propose a model for estimating the rate at which
additional DNA is accumulated as heterochromatin and euchromatin and also
predict the minimum genome size for Drosophila. According to comparative
phylogenetic approaches, the rates of change of heterochromatin differ
strikingly between Drosophila subgenera. While these subgenera differ in
karyotype, there were no differences by chromosome number, suggesting
other structural changes may influence accumulation of heterochromatin.
Measurements were taken for both sexes, allowing the visualization of
genome size and heterochromatin changes for the hypothetical path of XY
sex chromosome differentiation. Additionally, the model presented here
estimates a minimum genome size in Sophophora remarkably close to the
smallest insect genome measured to date, in a species over 200 million
years diverged from Drosophila.