Final answer:
After DNA replication, each daughter chromatid will exhibit hemi methylated DNA and half of the H3 histones with H3K9me3 modifications, reflecting the semi-conservative nature of DNA replication and the subsequent need for enzymatic restoration of the original heterochromatic modification states.
Step-by-step explanation:
After DNA replication, each daughter chromatid will have hemimethylated DNA and half of the H3 histones with H3K9me3 modifications. DNA replication is a semi-conservative process where the parental strands of DNA separate and each serves as a template for new DNA strands to be synthesized. Subsequently, the new DNA strand is synthesized alongside the parental DNA strand, resulting in daughter strands each consisting of one old and one new DNA strand.
Since the original heterochromatic region had fully methylated DNA sites, after replication, these sites are initially hemimethylated because only the parental strand carries methylation. The new strand needs to be methylated after replication to restore the fully methylated state. Similarly, histone modifications such as H3K9me3 mark heterochromatin but histones are randomly distributed between the daughter strands. Therefore, only half of the original H3 histones with modifications will be present on each new nucleosome. The rest are new H3 histones that will require modification by cellular enzymes to maintain the heterochromatic state.