Histone H2A variants have different fates in the new embryo.

<p><b>A</b>) A schematic of paternal and maternal chromatin processing before and after fertilization. <b>B–F</b>) Immunostaining of embryos in different stages show that HTAS-1 (green in merged images) is retained in paternal (p) chromatin while HTZ-1 (red) is removed from paternal and maternal (m) chromatin in the 1-cell embryo. DNA is shown in blue. The scale bar represents 10 µm and applies to all panels. <b>B</b>) 1-cell embryos after fertilization. The oocyte pronucleus is undergoing meiotic divisions while the paternal pronucleus is decondensing. <b>C</b>) After DNA replication, the pronuclei migrate to the center of the embryo. <b>D</b>) Chromosomes align on the metaphase plate before segregation. <b>E</b>) 2-cell embryos <b>F</b>) 4-cell embryos. P₂ marks the transcriptionally silent P₂ germline precursor cell.