Mealybug Chromosome Cycle as a Paradigm of Epigenetics

Figure 2

Male and female P. citri embryos at syncytial blastoderm (7th mitotic division, 128–256-nuclei stage). In the male embryo (left), it is possible to observe different stages of heterochromatinization. Heterochromatinization proceeds as a wave from one pole (bottom right) of the embryo, where nuclei show a fully developed chromocenter, toward the other one (top left), where nuclei still lack a chromocenter. Heterochromatinization selectively affects the paternal chromosomes (blue). In the female embryo (right), paternal and maternal (pink) chromosomes present the same degree of compaction and remain active.